Question

Each person in a random sample of 226 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 μ_males − μ_females. 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

Two-Sample T-Test and CI

Method

μ₁: mean of Males

µ₂: mean of Females

Difference: μ₁ - µ₂

Equal variances are not assumed for this analysis.

Descriptive Statistics

Sample	N	Mean	StDev	SE Mean
Sample 1	226	15.3	11.3	0.75
Sample 2	301	14.1	11.8	0.68

Estimation for Difference

Difference	95% CI for Difference
1.20	(-0.79, 3.19)

Test

Null hypothesis	H₀: μ₁ - µ₂ = 0
Alternative hypothesis	H₁: μ₁ - µ₂ ≠ 0

T-Value	DF	P-Value
1.18	495	0.237