10.27 Kuwaiti men versus Swedish men The following descriptive statistics were obtained from a study (Saud al-Obaidi et al., Journal of Rehabilitation Research and Development, vol. 40, 2003) that aimed to compare the weight of Kuwaiti men with Swedish men between the ages of 20 to 29 years.

Group size Mean weight (kg)
Standard deviation Kuwaiti men 15 81.57 26.26 Swedish men 15 70.73 12.56

a. Using software (such as StatCrunch) which can conduct analyses using summary statistics, find the test statistic and P-value for H0: μ1 = μ2 against Ha: μ1 • μ2.
Interpret and explain what (if any) effect a country has on the mean weight of its men.

b. Do you think that the weights were approximately normal for each country? Why or why not? How does this affect the validity of the analysis in part a?