Question

Each person in a random sample of 225 male teenagers and a random sample of 301 female teenagers was asked how many hours he or she spent online in a typical week. The sample mean and standard deviation were 15.3 hours and 11.3 hours for males and 14.1 and 11.8 for females. (Use a statistical computer package to calculate the P-value. Use μmales − μfemales. Round your test statistic to two decimal places, your df down to the nearest whole number, and your P-value to three decimal places.)

t =

df =

P =

Answer 1

The statistical software output for this problem is:

Two sample T summary hypothesis test: Hi : Mean of Population 1 H2 : Mean of Population 2 Hi-H2 : Difference between two means Ho: P1 - H2 = 0 HA: H1 - H270 (without pooled variances) Hypothesis test results: Difference Sample Diff. Std. Err. DF T-Stat P-value H1 - H2 1.2 1.0149396 493.28538 1.1823363 0.2376

Hence,

t = 1.18

df = 493

P = 0.238