Question

Researchers collected a simple random sample of the times that 81 college students required to earn their bachelor’s degrees. The sample has a mean of 4.8 years and a standard deviation of 2.2 years. Use a 0.05 significance level to test the claim that the mean time for all college students is greater than 4.5 years.

Answer 1

Answer:

0.4459

Step-by-step explanation:

Let the random age variable, X = 4.5; mean,∪ = 4.8; standard deviation, α = 2.2

By comparing P ( 0≤ Z ≤ 4,8)

P(Z ≤ X - ∪/α) = P(Z ≤ 4.5 - 4.8/2.2) = P(Z ≤ - 0.136)

Using the table: P(0≤ Z ≤ 1) = 0.0541

P(Z > 1) = (0.5 - 0.0541) = 0.4459

∴ P(Z > 4.5) = 0.4459