Question

7.74 Beverage consumption. The results in the previous exercise were based on two national surveys with a very large number of individuals. Here is a study that also looked at beverage consumption, but the sample sizes were much smaller. One part of this study compared 20 children who were 7 to 10 years old with 5 37 to 19.9 oz. The authors state that the difference is statistically significant with P<0.01. information you would need to compute a confidence interval for the increase, and outline the procedure that you would use for the computations. Do you think that a confidence interval would provide useful additional information? Explain why or why not. children who were 11 to 13. day, while the older ones averaged 14.5 oz. The standard deviations were 10.7 oz and 8.2 oz, respectively. The younger children consumed an average of 8.2 oz of sweetened drinks per (a) Do you think that it is reasonable to assume that these data are Normally distributed? Explain why or why not. (Hint: Think about the 68–95–99.7 rule.) (b) Using the methods in this section, test the null hypothesis that the two groups of children consume equal amounts of sweetened drinks versus the two-sided alternative. Report all details of the significance-testing procedure with your conclusion. (c) Give a 95% confidence interval for the difference in means. (d) Do you think that the analyses performed in parts (b) and (c) are appropriate for these data? Explain why or why not. (e) The children in this study were all participants in an intervention study at the Cornell Summer Day Camp at Cornell University. To what extent do you think that these results apply to other groups of children?

Answer 1