Data for Exercise 7.54

Twin

Format

A data frame/tibble with nine observations on three variables

twinA

score on intelligence test without drug

twinB

score on intelligence test after taking drug

differ

twinA - twinB

References

Kitchens, L. J. (2003) Basic Statistics and Data Analysis. Pacific Grove, CA: Brooks/Cole, a division of Thomson Learning.

Examples


qqnorm(Twin$differ)
qqline(Twin$differ)

shapiro.test(Twin$differ)
#> 
#> 	Shapiro-Wilk normality test
#> 
#> data:  Twin$differ
#> W = 0.90449, p-value = 0.2792
#> 
t.test(Twin$twinA, Twin$twinB, paired = TRUE)
#> 
#> 	Paired t-test
#> 
#> data:  Twin$twinA and Twin$twinB
#> t = 2.4, df = 8, p-value = 0.04318
#> alternative hypothesis: true difference in means is not equal to 0
#> 95 percent confidence interval:
#>  0.07832989 3.92167011
#> sample estimates:
#> mean of the differences 
#>                       2 
#>