A standard painkiller is known to bring relief in 3.5 minutes on average LaTeX: \muμ. A new painkiller is hypothesized to bring faster relief to patients. A sample of 40 patients are given the new painkillers. The sample yields a mean of 3.0 minutes and a standard deviation of 1.1 minutes. Using a level of significance LaTeX: \alpha = 0.05α = 0.05, the rejection region for the test is:

Reject H0 if Z ≤ critical value

- 2.8747978 ≤ 1.645

Step-by-step explanation:

Setting the null and alternative hypothesis :

H0 : μ = 3.5

H1 : μ < 3.5

Sample size (n) = 40

Mean (m) = 3 minutes

Standard deviation (s) = 1.1 minutes

Test statistic : Z = (m - μ) / (s/√n)

Z = (3 - 3.5) / (1.1/√40)

Z = - 0.5 / 0.1739252

Z = - 2.8747978

Zcritical at α 0.05 = 1.645

This is a left tailed test :

Hence rejection region:

Reject H0 if Z ≤ critical value

- 2.8747978 ≤ 1.645

1.5%

step-by-step explanation:

-2

7 - 9 = -2

reversed:

-2 + 9 = 7