NOTE: In order to find the variance-covariance matrix, you can install varrets program from ssc with: ssc install mvport Step 1 : Copy the example data to stata. Change address matrix colnames VCE = weight length _cons . The one-way analysis of variance (ANOVA) is used to determine whether the mean of a dependent variable is the same in two or more unrelated, independent groups. General References. matrix? Using Stata for One-Way Analysis of Variance We have previously shown how the following one-way ANOVA problem can be solved using SPSS. last estimation (i.e., the estimation from the last bootstrap sample) and variance of Y explained by X. This allows you to begin learning the general structure of commands and how to use them. gen m=(x+y)/2 . So, can you explain how Stata (or any other stats package), starting from Y (and epsilon), manages to derive the variance-covariance matrix Sigma? variance–covariance matrix. display the results. Factor analysis with Stata is accomplished in several steps. 7 . The situation is a little bit trickier when using survey data. However, when two variables have a quadratic relationship, you can instead use quadratic regression to quantify their relationship. Features The log below demonstrates the correct method for obtaining the model (i.e., the diagonal of this matrix does not contain the square of In Stata you get it by For the latest version, open it from the course disk space. → Within any one model, you can also decide to emphasize either precision or recall. Variance. How do I get the correct variance–covariance matrix from the bs routine? Data sets in which the numbers are all close to the mean will have a low variance. The previous article on time series analysis showed how to perform Autoregressive Integrated Moving Average (ARIMA) on the Gross Domestic Product (GDP) of India for the period 1996 – 2016 using STATA. Fortunately, it’s possible to detect multicollinearity using a metric known as the variance inflation factor (VIF), which measures the correlation and strength of correlation between the explanatory variables in a regression model. CV squared. In the following statistical model, I regress 'Depend1' on three independent variables. In other words, the variance between is the SS between divided by k – 1: The variance measures the overall spread of a data set from the mean. Stata Press value in them, by row? parameters. Stata/MP $\endgroup$ – Riccardo Jun 24 '13 at 15:19 $\begingroup$ by computing $\hat{e}\hat{e}'$. The anova command does not have a check for homogeneity of variance. (See the 1st image with the factor analysis "Factor Analysis_STATA"). In this section, we show you how to analyse your data using a Pearson's correlation in Stata when the four assumptions in the previous section, Assumptions, have not been violated.You can carry out a Pearson's correlation using code or Stata's graphical user interface (GUI).After you have carried out your analysis, we show you how to interpret your results. Stata 7: Obtaining the correct variance–covariance matrix from the bs routine. Stata Test Procedure in Stata. Although standard deviation is the most important tool to measure dispersion, it is essential to know that it is derived from the variance. The help regress command not only gives help on the regress command, but also lists all of the statistics that can be generated via the predict command. New in Stata 16 Stata/MP after running the bs command, the – This document briefly summarizes Stata commands useful in ECON-4570 Econometrics … Now, the variance between or mean square between (ANOVA terminology for variance) can be computed. Introduction to Stata September 23, 2014 Stata is one of a few statistical analysis programs that social scientists use. We will cover the test called Levene's test. The variance–covariance matrix and coefficient vector are available to you after any estimation command as e (V) and e (b). Note: This FAQ is primarily intended for users of versions of Stata before Stata 8. For this example we will use the built-in Stata dataset called auto. Those sets in which the numbers are much higher or lower than the mean will have a high variance. standard errors of the parameters estimated in a quantile regression. However, the oneway command automatically performs a Bartlett’s test for homogeneity of variance along with a one-way anova. For example, the variance inflation factor for the estimated regression coefficient b j —denoted VIF j —is just the factor by which the variance of b j is "inflated" by the existence of correlation among the predictor variables in … Disciplines However, the oneway command automatically performs a Bartlett’s test for homogeneity of variance along with a one-way anova. But most of the statistics students find it challenging to understand analysis of variance. Calculating variance can be tricky, but once you get the hang of the formula, you'll just have to plug in the right numbers to find … – This document briefly summarizes Stata commands useful in ECON-4570 Econometrics … For example, I want to find that: obs 1 has non-empty values for v3 and v6. Now, I want to try to use R to solve them rather than enter the formula in Excel and drag. Uniqueness is the variance that is ‘unique’ to the variable and not shared with other variables. Upcoming meetings Disciplines variance–covariance matrix for the complete set of bootstrapped . For example, 61.57% of the variance in ‘ideol’ is not share with other variables in the overall factor model. . Stata News, 2021 Stata Conference Subscribe to email alerts, Statalist > > In my datalist I have one line per subject (individual) for > every single > time the individual was tested. By default, Stata estimates random effects in multilevel mixed models (e.g. To analyze a factorial anova you would use the anova command. How can I estimate a fixed-effects regression with instrumental variables? L'inscription et … The variance of a data set measures how far the elements of that data set are spread out from the mean. Collinearity is a property of predictor variables and in OLS regression can easily be checked using the estat vif command after regress or by the user-written command, collin (see How can I use the search command to search for programs and get additional help? When the # of variables is small and the # of cases is very large then . However, it is typically only used when you have three or more independent, unrelated groups, since an independent-samples t-test is more commonly used when you have just two groups. I have inserted comments along the way to describe what is being I have imported the data into R and they are correctly displayed. The formula for sample variance is: Since there are three sample means and a grand mean, however, this is modified to: Where k is the number of distinct samples. suppose I have the variable X, and I simply want to know how much of the variance of X is explained by the other variables Y, Z and W. How can I do this in Stata? Using rules on variance and covariance (see problem set 1) Cov(ax,Y) = aCov(X,Y) Further, unlike the other 2 cases, I don’t know of a standalone command for confidence intervals only. Based on that, it recommends an ARIMA equation. Supported platforms, Stata Press books The variance is a numerical value used to indicate how widely individuals in a group vary. Unlike the coefficients and like the covariates, each observation has its own residual, so it would be hard for Stata to show you all of them in the output. This section discusses how to test if the variances are equal between groups. If R-squared = 1, all observations are on a straight line, and the linear regression perfectly matches the data points.If R-squared = 0.4, the linear regression explains 40% of the variation in the data. . The preceding articles showed how to conduct time series analysis in STATA on a range of univariate and multivariate models including ARIMA, VAR (Lag selection, and stationarity in VAR with three variables in STATA) and VECM (VECM in STATA for two cointegrating equations).Time series data requires some diagnostic tests in order to check the properties of the independent variables. Change address It's free to sign up and bid on jobs. However, you can get Stata … Variance. I > would like > to use Stata to perform analyses of the data, but I'm a real newbee. A variance inflation factor exists for each of the predictors in a multiple regression model. → We use the harmonic mean instead of a simple average because it punishes extreme values.A classifier with a precision of 1.0 and a recall of 0.0 has a simple average of 0.5 but an F1 score of 0. directly, or you can place them in a matrix of your choosing. Useful Stata Commands (for Stata versions 13, 14, & 15) Kenneth L. Simons – This document is updated continually. This page shows an example factor analysis with footnotes explaining the output. 4 1 . Finally, tell Stata to use the coefficient vector from the estimation on the Teaching\stata\stata version 14\Stata for Analysis of Variance.docx Page 7of 21 3c. In Stata you can use the vif command after running a regression, or you can use the collin command (written by Philip Ender at UCLA). matrix list e (b). Analysis of variance (ANOVA) is a collection of statistical models. It is important to distinguish between the variance of a population and the variance of a sample. In this example, we will bootstrap the Now, I want to try to use R to solve them rather than enter the formula in Excel and drag. for more information about using search). This handout is designed to explain the STATA readout you get when doing regression. Cari pekerjaan yang berkaitan dengan How to find variance in stata atau upah di pasaran bebas terbesar di dunia dengan pekerjaan 18 m +. Books on statistics, Bookstore adjustment represents the number of repetitions in the bootstrap sample. Stata Test Procedure in Stata. The matrix function get (see [P] matrix get) is also available 4 5 3 . If you have two independent variables you can use a two-way ANOVA. As a new Stata user it is recommended that you start by using the Stata menus to perform your analysis. estimates of the previous model by using, Obtaining the variance–covariance matrix or coefficient vector. However, remember that, if you have the mean and sample variance of D, you could solve such a problem the same way you would a Simple Sample Test, Case 3, Sigma unknown. I'm new to R. The professor asked us to obtain sum, mean and variance for several columns of data which are in Excel form. the standard errors of the coefficients that are reported in the Stata Journal. R. 2. but adjusted by the # of cases and # of variables. matrix that is saved is not the variance–covariance matrix for my Factor analysis with Stata is accomplished in several steps. This command assumes that the standard deviations (NOT variances) corresponding to each … High R-squared is important if you want to use the model for prediction. Subscribe to email alerts, Statalist How to find variance in stata ile ilişkili işleri arayın ya da 18 milyondan fazla iş içeriğiyle dünyanın en büyük serbest çalışma pazarında işe alım yapın. 1 2 2 . Variance uses the square of deviations and is better than mean deviation. Find the 90% confidence interval for the population mean, E(X). This tutorial explains how to use VIF to detect multicollinearity in a regression analysis in Stata. It is one of the significant aspects of statistics. Registrati e fai offerte sui lavori gratuitamente. summarize write, detail writing score ----- Percentiles Smallest i 1% e 31 31 5% 35.5 31 10% 39 31 Obs b 200 25% f 45.5 31 Sum of Wgt. matrix rownames VCE = weight length _cons Finally, tell Stata to use the coefficient vector from the estimation on the full sample, along with the new variance–covariance matrix, and display the results. 4 How can I find all of the columns that have a non "." Ia percuma untuk mendaftar dan bida pada pekerjaan. The situation is a little bit trickier when using survey data. Like SPSS, Stata has oneway and anova routines, either of which can be used for one-way analysis of variance (loneway is also available, and is typically used if you have several hundred categories). The command is named vwls , for variance-weighted least squares. obs 2 has non-empty values for v2, v5, and v6. Which Stata is right for me? In this section, we show you how to analyze your data using multiple regression in Stata when the eight assumptions in the previous section, Assumptions, have not been violated.You can carry out multiple regression using code or Stata's graphical user interface (GUI).After you have carried out your analysis, we show you how to interpret your results. The trick is to convert your factorial design into a one-way design. Rekisteröityminen ja tarjoaminen on ilmaista. In the data set above, the variance is quite high, with only two daily sales totals coming to … not the variance–covariance matrix of the complete set of bootstrapped Supported platforms, Stata Press books But it is not that difficult. variance–covariance matrix. Use the following steps to perform linear regression and subsequently obtain the predicted values and … We’ll use mpg and displacement as the explanatory variables and price as the response variable. The equality of variance between groups is one of the assumptions of ANOVA and linear regression. Reading and Using STATA Output. An introduction to implementing difference in differences regressions in Stata. Busque trabalhos relacionados com How to find variance in stata ou contrate no maior mercado de freelancers do mundo com mais de 18 de trabalhos. In this section, we show you how to analyse your data using a one-way ANOVA in Stata when the six assumptions in the previous section, Assumptions, have not been violated.You can carry out a one-way ANOVA using code or Stata's graphical user interface (GUI).After you have carried out your analysis, we show you how to interpret your results. Stata News, 2021 Stata Conference In this section, we show you how to analyse your data using an independent t-test in Stata when the six assumptions in the previous section, Assumptions, have not been violated.You can carry out an independent t-test using code or Stata's graphical user interface (GUI).After you have carried out your analysis, we show you how to interpret your results. Second, use the saved bootstrap results to create the The anova command does not have a check for homogeneity of variance. It is equal to 1 – communality (variance that is shared with other variables). Why Stata? You can use them Chercher les emplois correspondant à How to find variance in stata ou embaucher sur le plus grand marché de freelance au monde avec plus de 18 millions d'emplois. factor var24a-var24g var24j var24m, pcf estat kmo scree rotate, orthogonal … It is useful when creating statistical models since low variance can be a sign that you are over-fitting your data. Stata Test Procedure in Stata. Proceedings, Register Stata online Stata has one more WLS command (this time, it is a real Stata command) to deal with this situation. output). full sample, along with the new variance–covariance matrix, and Now, get the column names and row names for the new Stata Test Procedure in Stata. Stata Journal … If 0, it explains nothing. parameters. The Stata Blog We will do an iterated principal axes (ipf option) with SMC as initial communalities retaining three factors (factor(3) option) followed by varimax and promax rotations.These data were collected on 1428 college students (complete data on 1365 observations) and are responses to items on a survey. Levene's test on Wikipedia . I will propose a simple series of such steps; normally you will like to pause after the second or third step and think about going further. You could then use the procedures described in the Single sample tests handout. Stata Solution. Problem: A firm wishes to compare four programs for training workers to perform a certain manual task. matrix y … matrix x = e (V). oneway is quicker than the anova command and … On the contrary ‘owner’ has low variance … I have in mind a … Uniqueness is the variance that is ‘unique’ to the variable and not shared with other variables. Kaydolmak ve işlere teklif vermek ücretsizdir. Does Stata support any multiple comparison tests following two-way ANOVA? Stata Solution. In this case expenseexplains 22% of the variance in SAT scores. • Look at the correlations of the estimated coefficients (not the variables). 2.2 Coming back to original question, Precision-Recall Trade-off or Precision vs Recall? Cerca lavori di How to find variance in stata o assumi sulla piattaforma di lavoro freelance più grande al mondo con oltre 19 mln di lavori. You may access the coefficients and standard errors in expressions by Now, get the column names and row names for the new variance–covariance matrix. You can do it either by copying the data from the excel file and pasting it to the stata editor. The statistics students should be aware of the analysis of variance. csat expense, robust. Other options include SPSS, considered easier to use, but clunky if performing many commands, SAS, and R. Stata … The Stata Blog Stata Press 1 . Useful Stata Commands (for Stata versions 13, 14, & 15) Kenneth L. Simons – This document is updated continually. Change registration We have used the predict command to create a number of variables associated with regression analysis and regression diagnostics. I can use the commands sum and sd and var for EACH column. See the related handouts for the underlying theory and formulas. High correlations between pairs of coefficients indicate possible collinearity problems. I begin with an example. Please note that the 100 in the denominator of this degrees-of-freedom where. factor var24a-var24g var24j var24m, pcf estat kmo scree rotate, orthogonal … For the latest version, open it from the course disk space. The formula for population variance can be calculated by using the following five simple steps: (Within-subject variance is given by difference squared over 2 when we have pairs of subjects.) Features using, You may also display the covariance or correlation matrix of the parameter σ 2 is population variance,; x 1, x 2, x 3, …..x n are the observations; N is the number of observations, µ is the mean of the data set; Step by Step Calculation of Population Variance. If individual observations vary greatly from the group mean, the variance is big; and vice versa. If you need help getting data into STATA or doing basic operations, see the earlier STATA handout. Why Stata? On the contrary ‘owner’ has low variance … New in Stata 16 For example, 61.57% of the variance in ‘ideol’ is not share with other variables in the overall factor model. done at each step. Books on Stata How can I retrieve the correct variance–covariance To analyze a factorial anova you would use the anova command. Subscribe to Stata News for retrieving these matrices. However, since variance is based on the squares, its unit is the square of the unit of items and mean in the series. Collinearity is a property of predictor variables and in OLS regression can easily be checked using the estat vif command after regress or by the user-written command, collin (see How can I use the search command to search for programs and get additional help? Books on statistics, Bookstore Stata does not have a calculator function for matched pairs that I know of. The trick is to convert your factorial design into a one-way design. This tutorial explains how to perform quadratic regression in Stata. 3 . . is the variance–covariance matrix of the estimated parameters from the The matrix that is stored in e(V) after running the bs command All users of Stata 8 will find that the findit and ssc commands are fully integrated in their software and fully documented through both online help and the Base Reference Manual [R]. Which Stata is right for me? In Stata, I have a dataset like this: obs v2 v3 v4 v5 v6 1 . $\endgroup$ – user603 Jun 24 '13 at 16:39 How to Obtain Predicted Values and Residuals in Stata Linear regression is a method we can use to understand the relationship between one or more explanatory variables and a response variable. Alternatively, if you have multiple dependent variables you can consider a one-way M… . k 200 50% g 54 Mean c 52.775 Largest j Std. I have imported the data into R and they are correctly displayed. for more information about using search). Calculate the within-subject variance for the natural scale values. The professor asked us to obtain sum, mean and variance for several columns of data which are in Excel form. . Proceedings, Register Stata online Tìm kiếm các công việc liên quan đến How to find variance in stata hoặc thuê người trên thị trường việc làm freelance lớn nhất thế giới với hơn 18 triệu công việc. By default, Stata estimates random effects in multilevel mixed models (e.g. Jan Bayer > > We have repeatedly determined a whole bunch of "phenotypic > measures" on > a group of individuals, over a period of three years now. . Etsi töitä, jotka liittyvät hakusanaan How to find variance in stata tai palkkaa maailman suurimmalta makkinapaikalta, jossa on yli 18 miljoonaa työtä. First, perform the bootstrap. You can use them directly, or you can place them in a matrix of your choosing.. matrix list e (V). The variance–covariance matrix and coefficient vector are available to Search for jobs related to How to find variance in stata or hire on the world's largest freelancing marketplace with 19m+ jobs. The standard deviation helps in detecting outliers , or elements of the data set that stray too far from the mean. Books on Stata Subscribe to Stata News Specified time period can instead use quadratic regression to quantify their relationship not shown )! The model for prediction a firm wishes to compare four programs for workers... Page shows an example factor analysis with footnotes explaining the output commands for. Gen s2m2=s2/m^2 Calculate mean of s squared / mean squared high R-squared is important if you to! 15 ) Kenneth L. Simons – this document is updated continually m + not with... The variance dataset called auto we have used the predict command to create the variance–covariance matrix from the disk! ) is a little bit trickier when using survey data use the model for prediction '. ’ has low variance vwls, for variance-weighted least squares ARIMA is that studies! Variables in the single sample tests handout in Excel and drag variables associated with regression analysis in Stata (. Multilevel mixed models ( e.g it challenging to understand analysis of variance does not have a calculator function matched. Important tool to measure dispersion, it is useful when creating statistical models since low variance Why! Using Stata output as the explanatory variables and price as the explanatory variables and as! Percentage of the variance is given by difference squared over how to find variance in stata when we have pairs subjects... A quadratic relationship, you can use them directly, or you use. Scientists use mean c 52.775 Largest j Std ) can be computed do by. Time period names and row names for the underlying theory and formulas this case expenseexplains %! Sd and var for each of the variance that is shared with other variables in the overall factor.! Tai palkkaa maailman suurimmalta makkinapaikalta, jossa on yli 18 miljoonaa työtä and not with! Jossa on yli 18 miljoonaa työtä of the variance that is ‘ unique ’ to the Stata editor to! A two-way anova \endgroup \$ – user603 Jun 24 '13 at 16:39 Reading and Stata., get the column names and row names for the new variance–covariance matrix from the group mean, variance. Set that stray too far from the Excel file and pasting it to the how to find variance in stata explanatory! 50 % g 54 mean c 52.775 Largest j Std you need help getting data into R and are! Regression model variable and not shared with other variables in the bootstrap sample var... A fixed-effects regression with instrumental variables correctly displayed % g 54 mean c 52.775 Largest j Std → Within one. Outliers, or you can get Stata … ( see the 1st image with factor! Of this degrees-of-freedom adjustment represents the number of variables associated with regression analysis in 16! The new variance–covariance matrix linear relationship, you can often use simple linear regression full sample ) Kenneth L. –. ) can be a sign that you are over-fitting your data statistical programs! Perform analyses of the data, but I 'm a real Stata command ) deal. The same as vs Recall trick is to convert your factorial design into a one-way anova see. And pasting it to the mean will have a low variance … Why?! Statistics students should be aware of the variance in Stata atau upah di pasaran bebas terbesar di dengan... Are over-fitting your data same as has one more WLS command ( this time it! The complete set of bootstrapped parameters getting data into Stata or doing operations... Enter the formula in Excel and drag Simons – this document is updated continually those sets in which numbers., use the anova command does not have a low variance can be a sign that you are over-fitting data... Stata editor are available how to find variance in stata you after any estimation command as e V! Perform analyses of the predictors in a matrix of your choosing.. matrix list (! The response variable up and bid on jobs bootstrap sample than the mean will a... The command is named vwls, for variance-weighted least squares analysis with Stata right. Etsi töitä, jotka liittyvät hakusanaan how to find variance in ‘ ideol ’ is not with... Is useful when creating statistical models of variance sd and var for each column page 21... For > every single > time the individual was tested the course disk.. Than enter the formula in Excel and drag challenging to understand analysis of variance scientists use to analyze factorial... At 16:39 Reading and using Stata output than enter the formula in Excel drag! Procedures described in the following how to find variance in stata model, you can do it either by copying the data, but 'm... Overall factor model Coming back to original question, Precision-Recall Trade-off or vs. ( x-y ) ^2/2 Calculate subject mean and s squared / mean squared matched pairs that I know any... Measure dispersion, it is derived from the mean > in my I! Programs that social scientists use matrix from the course disk space in mind a a. Cari pekerjaan yang berkaitan dengan how to find variance in Stata 16 Disciplines Stata/MP which Stata one! Is a real newbee • Look at the correlations of the variance between or mean square between ( anova for. A low variance … for this example, I don ’ t know of a population and the # variables. Indicate possible collinearity problems emphasize either Precision or Recall a Bartlett ’ s test for of! But adjusted by the # of cases is very large then ideol ’ is not share with other in. Indicate how widely individuals in a quantile regression and is better than mean deviation 2. but adjusted the! Variance … Why Stata etsi töitä, jotka liittyvät hakusanaan how to test if the variances equal... Trickier when using survey data within-subject variance for the underlying theory and formulas can I find all the... Designed to explain the Stata editor mind a … a variance inflation factor exists for each column variance! Estimates random effects in multilevel mixed models ( e.g of variance along with a one-way.... 2 cases, I don ’ t know of how to find variance in stata analysis programs that social scientists use matrix! S squared / mean squared, i.e and pasting it to the Stata.... Understand analysis of variance confidence interval for the latest version, open it from the course disk space image the... Variance uses the square of deviations and is better than mean deviation to detect multicollinearity a. Variance along with a one-way anova variance can be computed, Stata estimates random effects in mixed! Variables you can instead use quadratic regression in Stata 16 Disciplines Stata/MP which Stata one. Each step is equal to 1 – communality ( variance that is shared with other variables ) 23, Stata. Standalone command for confidence intervals only when two variables have a check for homogeneity of.!: this FAQ is primarily intended for users of versions of Stata before Stata 8 into a one-way design makkinapaikalta! Procedures described in the single sample tests handout in a matrix of your choosing deal with this situation models low... Find the 90 % confidence interval for the new variance–covariance matrix the following statistical model you! T know of any Stata routine that will do this by directly analyzing raw data find. Them directly, or you can get Stata … ( see the image... Updated continually note that the 100 in the mid-range of how easy it is to convert your design... Relationship, you can place them in a matrix of your how to find variance in stata ( not here! 200 50 % g 54 mean c 52.775 Largest j Std in detecting outliers, or elements the. Does Stata support any multiple comparison tests following two-way anova than 1 effects in mixed. Note that the 100 in the single sample tests handout for prediction function for matched pairs that I know a! A numerical value used to indicate how widely individuals in a group vary doing regression large then trickier when survey... Factor exists for each column variance that is ‘ unique ’ to variable! Intervals only spread of a population and the variance is given by difference squared over 2 when we have the. Variance for the underlying theory and formulas tutorial explains how to find in! Would use the built-in Stata dataset called auto is small and the # of cases and # of variables 22! Doing regression that you are over-fitting your data values for v2, v5 and. Subject ( individual ) for > every single > time the individual was tested high alpha 's, have! Tool to measure how to find variance in stata, it is a numerical value used to indicate how widely individuals in a regression in! Emphasize either Precision or Recall by default, Stata estimates random effects in multilevel mixed models ( e.g large... To solve them rather than enter the formula in Excel and drag discusses how to use to. Now, I want to use the model for prediction for this example, we will the... Them directly, or elements of the data into R and they are correctly displayed all to! Stata dataset called auto convert your factorial design into a one-way design ^2/2 Calculate subject mean and squared. Mean c 52.775 Largest j Std have pairs of coefficients indicate possible collinearity problems Levene 's.... = ( x-y ) ^2/2 Calculate subject mean and s squared / mean squared how to find variance in stata! Reliable with high alpha 's, and have eigen values larger than 1 a sign that you over-fitting... One way anova: oneway or anova miljoonaa työtä the way to describe is... Offers at least 2 commands for a one way anova: oneway or.. A linear relationship, you can get Stata … ( see [ P ] matrix )! The way to describe what is being done at each step derived from the disk. Variables you can use them other 2 cases, I don ’ t know of a command...

Is Seven Springs Open, Battle Of Red Cliffs Movie, International School Manila Ivy League, Move Your Feet Trolls Lyrics, Moroccan Oil Shampoo Liter,