Video Games: Costs The two biggest markets for people to purchase online video games for consoles is the Xbox Marketplace and PlayStation Store. Each online store sells video games at various prices.

Suppose a random sample of 50 different games and their prices were independently selected from both the PlayStation Store and the Xbox Marketplace. The PlayStation Store had an average price of x1 5$28.75 while the Xbox Marketplace had an average price of x2 5$26.89.

(a) Check Requirements Suppose s1 and s2 are unknown, what distribution does x1 2x2 follow?

Explain.

(b) Given s1 5 3 and s2 5 2, find a 95% confidence interval for m1 2m2.

(c) Check Requirements Suppose s1 and s2 are unknown, but from the random samples, you know s1 5$2.75 and s2 5$2.15. What distribution approximates the x1 2x2 distribution? What are the degrees of freedom? Explain.

(d) Find a 95% confidence interval for m1 2m2.

(e) If you have an appropriate calculator or computer software, find a 95% confidence interval for m1 2m2 using the degrees of freedom based on Satterthwaite’s approximation.

(f) Interpretation Based on the confidence intervals you computed, can you be 95% confident that m1 is greater than m2? Explain.

AppendixLO1