Description Usage Format Details Source Examples

Data from Tennessee's Student Teacher Achievement Ratio (STAR) project which was a large-scale, four-year study of the effect of reduced class size.

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A data frame with 26796 observations on the following 18 variables.

`id`

a factor - student id number

`sch`

a factor - school id number

`gr`

grade - an ordered factor with levels

`K`

<`1`

<`2`

<`3`

`cltype`

class type - a factor with levels

`small`

,`reg`

and`reg+A`

. The last level indicates a regular class size with a teachers aide.`hdeg`

highest degree obtained by the teacher - an ordered factor with levels

`ASSOC`

<`BS/BA`

<`MS/MA/MEd`

<`MA+`

<`Ed.S`

<`Ed.D/Ph.D`

`clad`

career ladder position of the teacher - a factor with levels

`NOT`

`APPR`

`PROB`

`PEND`

`1`

`2`

`3`

`exp`

a numeric vector - the total number of years of experience of the teacher

`trace`

teacher's race - a factor with levels

`W`

,`B`

,`A`

,`H`

,`I`

and`O`

representing white, black, Asian, Hispanic, Indian (Native American) and other`read`

the student's total reading scaled score

`math`

the student's total math scaled score

`ses`

socioeconomic status - a factor with levels

`F`

and`N`

representing eligible for free lunches or not eligible`schtype`

school type - a factor with levels

`inner`

,`suburb`

,`rural`

and`urban`

`sx`

student's sex - a factor with levels

`M`

`F`

`eth`

student's ethnicity - a factor with the same levels as

`trace`

`birthq`

student's birth quarter - an ordered factor with levels

`1977:1`

< ... <`1982:2`

`birthy`

student's birth year - an ordered factor with levels

`1977:1982`

`yrs`

number of years of schooling for the student - a numeric version of the grade

`gr`

with Kindergarten represented as 0. This variable was generated from`gr`

and does not allow for a student being retained.`tch`

a factor - teacher id number

Details of the original data source and the process of conversion to this representation are given in the vignette.

http://www.heros-inc.org/data.htm

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```
Loading required package: lme4
Loading required package: Matrix
'data.frame': 26796 obs. of 18 variables:
$ id : Factor w/ 11598 levels "100017","100028",..: 1 2 3 3 3 4 5 5 6 6 ...
$ sch : Factor w/ 80 levels "1","2","3","4",..: 28 52 41 41 41 64 40 40 22 22 ...
$ gr : Ord.factor w/ 4 levels "K"<"1"<"2"<"3": 1 1 2 3 4 1 1 2 1 2 ...
$ cltype : Factor w/ 3 levels "small","reg",..: 1 2 1 1 1 1 2 3 1 1 ...
$ hdeg : Ord.factor w/ 6 levels "ASSOC"<"BS/BA"<..: 2 3 2 3 2 2 2 2 2 3 ...
$ clad : Factor w/ 7 levels "NOT","APPR","PROB",..: 5 5 5 2 5 5 2 5 3 5 ...
$ exp : int 3 12 20 15 5 19 2 5 9 9 ...
$ trace : Factor w/ 6 levels "W","B","A","H",..: 2 1 1 2 1 1 1 1 2 2 ...
$ read : int 476 410 507 575 610 430 495 629 418 524 ...
$ math : int 602 444 572 620 655 484 576 592 489 567 ...
$ ses : Factor w/ 2 levels "F","N": 1 2 2 2 2 2 1 1 1 1 ...
$ schtype: Factor w/ 4 levels "inner","suburb",..: 1 2 2 2 2 3 3 3 1 1 ...
$ sx : Factor w/ 2 levels "M","F": 2 2 1 1 1 2 2 2 2 2 ...
$ eth : Factor w/ 6 levels "W","B","A","H",..: 2 1 1 1 1 1 1 1 2 2 ...
$ birthq : Ord.factor w/ 25 levels "1977:1"<"1977:2"<..: 14 15 15 15 15 14 12 12 14 14 ...
$ birthy : Ord.factor w/ 6 levels "1977"<"1978"<..: 4 4 4 4 4 4 3 3 4 4 ...
$ yrs : num 0 0 1 2 3 0 0 1 0 1 ...
$ tch : Factor w/ 1387 levels "1","2","3","4",..: 478 893 698 701 706 1102 679 684 351 359 ...
```

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