Inference (Two Populations), Chi-Squared Tests A study comparing children's reading age (in months) was developed using identical twin toddlers. One set of 6 twins played for 2 hours each day with educational toys (experimental group), the corresponding set of 6 twins played for 2 hours each day with non-educational toys (control group). The mean difference in reading age between the experimental group and control group of 6 sets of twins was -2.33 months and the standard deviation of the sample difference was 2.16 months. Set up a hypothesis test to determine if there is a difference between the 2 groups and use the appropriate sample test statistic to determine if the difference in reading age is significant at the 5% level.