Question

A police officer is concerned about speeds on a certain section of Interstate 95. The data accompanying this exercise show the speeds of 40 cars on a Saturday afternoon.

Highway Speed: 73 68 67 74 74 70 68 73 65 69 67 63 66 64 67 65 70 64 63 61 62 63 63 66 64 62 65 62 70 62 66 64 67 61 69 66 61 70 65 61

a. The speed limit on this portion of Interstate 95 is 65 mph. Specify the competing hypotheses in order to determine if the average speed is greater than the speed limit.

• H₀: μ = 65; H_A: μ ≠ 65

• H₀: μ ≥ 65; H_A: μ < 65

• H₀: μ ≤ 65; H_A: μ > 65

b-1. Calculate the value of the test statistic. (Round your answer to 3 decimal places.)

b-2. Find the p-value.

• 0.05  p-value < 0.10
• 0.01  p-value < 0.020
• p-value  0.10

• p-value < 0.01

• 0.020 p-value < 0.05

c. At α = 0.01, are the officer’s concerns warranted?

Answer 1