Each child was given a verbal skill test twice, both before and after completing a 4-week period
in the class. Let Y = score on exam at time 2 - score on exam at time 1. Hence, if the population
mean µ for Y is equal to 0, the class has no effect, on the average. For the four children in the
study, the observed values of Y are 8-5=3, 10-3=7, 5-2=3, and 7-4=3 (e.g. for the first child, the
scores were 5 on exam 1 and 8 on exam 2, so Y = 8-5=3). It is planned to test the null hypothesis
of no effect against the alternative hypothesis that the effect is positive, based on the following
results from a statistical software package:
variable y
number of cases 4
mean 4.000
standard deviation 2.000
standard error 1.000
2 Calculate the test statistic, and indicate whether the P-value was below 0.05, based on
using the appropriate table