In this problem, assume that the distribution of differences isapproximately normal. Note: For degrees of freedomd.f. not in the Student's t table, usethe closest d.f. that is smaller. Insome situations, this choice of d.f. may increasethe P-value by a small amount and therefore produce aslightly more \"conservative\" answer.

At five weather stations on Trail Ridge Road in Rocky MountainNational Park, the peak wind gusts (in miles per hour) for Januaryand April are recorded below.

Weather Station	1	2	3	4	5
January	139	120	126	64	78
April	108	115	100	88	61

Does this information indicate that the peak wind gusts arehigher in January than in April? Use α = 0.01. (Let

d = January − April.)(a) What is the level ofsignificance?


State the null and alternate hypotheses. Will you use aleft-tailed, right-tailed, or two-tailed test?

H₀: μ_d = 0;H₁: μ_d ≠ 0;two-tailed H₀: μ_d= 0; H₁: μ_d >0; right-tailed     H₀:μ_d = 0; H₁:μ_d < 0; left-tailedH₀: μ_d > 0;H₁: μ_d = 0;right-tailed

(b) What sampling distribution will you use? What assumptions areyou making?

The standard normal. We assume that d has anapproximately uniform distribution. The Student's t. Weassume that d has an approximately uniformdistribution.     The standard normal. Weassume that d has an approximately normal distribution.The Student's t. We assume that d has anapproximately normal distribution.

What is the value of the sample test statistic? (Round your answerto three decimal places.)