SIMS: Second International Mathematics Study data

In SASmixed: Data sets from "SAS System for Mixed Models"

Description

The SIMS data frame has 3691 rows and 3 columns.

Format

This data frame contains the following columns:

Pretot

a numeric vector giving the student's pre-test total score

Gain

a numeric vector giving gains from pre-test to the final test

Class

an ordered factor giving the student's class

Source

Littel, R. C., Milliken, G. A., Stroup, W. W., and Wolfinger, R. D. (1996), SAS System for Mixed Models, SAS Institute (section 7.2.2)

Kreft, I. G. G., De Leeuw, J. and Var Der Leeden, R. (1994), “Review of five multilevel analysis programs: BMDP-5V, GENMOD, HLM, ML3, and VARCL”, American Statistician, 48, 324–335.

Examples

str(SIMS)
if (require("lme4", quietly = TRUE, character = TRUE)) {
  options(contrasts = c(unordered = "contr.SAS", ordered = "contr.poly"))
  ## compare to output 7.4, p. 262
  print(fm1SIMS <- lmer(Gain ~ Pretot + (Pretot | Class), data = SIMS))
  print(anova(fm1SIMS))
}

Example output

'data.frame':	3691 obs. of  3 variables:
 $ Pretot: num  29 38 31 31 29 23 23 33 30 32 ...
 $ Gain  : num  2 0 6 6 5 9 7 2 1 3 ...
 $ Class : Factor w/ 190 levels "1","10","100",..: 1 1 1 1 1 1 1 1 1 1 ...
 - attr(*, "ginfo")=List of 7
  ..$ formula     :Class 'formula'  language Gain ~ Pretot | Class
  .. .. ..- attr(*, ".Environment")=<environment: R_GlobalEnv> 
  ..$ order.groups: logi TRUE
  ..$ FUN         :function (x)  
  ..$ outer       : NULL
  ..$ inner       : NULL
  ..$ labels      :List of 2
  .. ..$ Pretot: chr "Sum of pre-test core item scores"
  .. ..$ Gain  : chr "Gain in mathematics achievement score"
  ..$ units       : list()
Linear mixed model fit by REML ['lmerMod']
Formula: Gain ~ Pretot + (Pretot | Class)
   Data: SIMS
REML criterion at convergence: 22380.57
Random effects:
 Groups   Name        Std.Dev. Corr 
 Class    (Intercept) 3.80651       
          Pretot      0.09593  -0.64
 Residual             4.71548       
Number of obs: 3691, groups:  Class, 190
Fixed Effects:
(Intercept)       Pretot  
      7.060       -0.186  
Analysis of Variance Table
       Df Sum Sq Mean Sq F value
Pretot  1 2969.4  2969.4  133.54

SASmixed documentation built on May 2, 2019, 4:47 p.m.