# Semiconductor: Semiconductor split-plot experiment In SASmixed: Data sets from "SAS System for Mixed Models"

## Description

The `Semiconductor` data frame has 48 rows and 5 columns.

## Format

This data frame contains the following columns:

resistance

a numeric vector

ET

a factor with levels `1` to `4` representing etch time.

Wafer

a factor with levels `1` to `3`

position

a factor with levels `1` to `4`

Grp

an ordered factor with levels `1/1` < `1/2` < `1/3` < `2/1` < `2/2` < `2/3` < `3/1` < `3/2` < `3/3` < `4/1` < `4/2` < `4/3`

## Source

Littel, R. C., Milliken, G. A., Stroup, W. W., and Wolfinger, R. D. (1996), SAS System for Mixed Models, SAS Institute (Data Set 2.2(b)).

## Examples

 ```1 2 3 4 5 6 7 8``` ```str(Semiconductor) if (require("lme4", quietly = TRUE, character = TRUE)) { options(contrasts = c(unordered = "contr.SAS", ordered = "contr.poly")) print(fm1Semi <- lmer(resistance ~ ET * position + (1|Grp), Semiconductor)) print(anova(fm1Semi)) print((fm2Semi <- lmer(resistance ~ ET + position + (1|Grp), Semiconductor))) print(anova(fm2Semi)) } ```

### Example output

```'data.frame':	48 obs. of  5 variables:
\$ resistance: num  5.22 5.61 6.11 6.33 6.13 6.14 5.6 5.91 5.49 4.6 ...
\$ ET        : Factor w/ 4 levels "1","2","3","4": 1 1 1 1 1 1 1 1 1 1 ...
\$ Wafer     : Factor w/ 3 levels "1","2","3": 1 1 1 1 2 2 2 2 3 3 ...
\$ position  : Factor w/ 4 levels "1","2","3","4": 1 2 3 4 1 2 3 4 1 2 ...
\$ Grp       : Factor w/ 12 levels "1/1","1/2","1/3",..: 1 1 1 1 2 2 2 2 3 3 ...
- attr(*, "ginfo")=List of 7
..\$ formula     :Class 'formula'  language resistance ~ 1 | Grp
.. .. ..- attr(*, ".Environment")=<environment: R_GlobalEnv>
..\$ order.groups: logi TRUE
..\$ FUN         :function (x)
..\$ outer       :Class 'formula'  language ~ET
.. .. ..- attr(*, ".Environment")=<environment: R_GlobalEnv>
..\$ inner       :Class 'formula'  language ~position
.. .. ..- attr(*, ".Environment")=<environment: R_GlobalEnv>
..\$ labels      : list()
..\$ units       : list()
Linear mixed model fit by REML ['lmerMod']
Formula: resistance ~ ET * position + (1 | Grp)
Data: Semiconductor
REML criterion at convergence: 50.6505
Random effects:
Groups   Name        Std.Dev.
Grp      (Intercept) 0.3253
Residual             0.3334
Number of obs: 48, groups:  Grp, 12
Fixed Effects:
(Intercept)            ET1            ET2            ET3      position1
6.54000       -0.65333       -0.62333       -0.44667       -0.20000
position2      position3  ET1:position1  ET2:position1  ET3:position1
0.01333       -0.64333       -0.07333        0.27667        0.24333
ET1:position2  ET2:position2  ET3:position2  ET1:position3  ET2:position3
-0.45000        0.25667        0.24000        0.31000        0.49333
ET3:position3
0.32333
Analysis of Variance Table
Df  Sum Sq Mean Sq F value
ET           3 0.64740 0.21580  1.9415
position     3 1.12889 0.37630  3.3855
ET:position  9 0.80947 0.08994  0.8092
Linear mixed model fit by REML ['lmerMod']
Formula: resistance ~ ET + position + (1 | Grp)
Data: Semiconductor
REML criterion at convergence: 53.0862
Random effects:
Groups   Name        Std.Dev.
Grp      (Intercept) 0.3275
Residual             0.3246
Number of obs: 48, groups:  Grp, 12
Fixed Effects:
(Intercept)          ET1          ET2          ET3    position1    position2
6.43875     -0.70667     -0.36667     -0.24500     -0.08833      0.02500
position3
-0.36167
Analysis of Variance Table
Df  Sum Sq Mean Sq F value
ET        3 0.61371 0.20457  1.9415
position  3 1.12889 0.37630  3.5714
```

SASmixed documentation built on May 1, 2019, 9:18 p.m.