Gambling in public high schools. With the rapid growth in legalized gambling in the United States, there is concern that the involvement of youth in gambling activities is also increasing. University of Minnesota professor Randy Stinchfield compared the annual rates of gambling among Minnesota public school students (Journal of Gambling Studies, Winter 2001). Based on survey data, the following table shows the percentages of ninth-grade boys who gambled weekly or daily on any game (e.g., cards, sports betting, lotteries) for two years: LO3 Year 1 Year 2

(6 years later)

Number of ninth-grade boys in survey 21,484 23,199 Number who gambled weekly/daily 4,684 5,313

a. Are the percentages of ninth-grade boys who gambled weekly or daily on any game in the two years significantly different? (Use a = .01.)

b. Professor Stinchfield states that “because of the large sample sizes, even small differences may achieve statistical significance, so interpretations of the differences should include a judgment regarding the magnitude of the difference and its public health significance.” Do you agree with this statement? If not, why not? If so, obtain a measure of the magnitude of the difference between the two years and attach a measure of reliability to the difference.