Question

(CO 5) An advocacy group claims that the mean braking distance of a certain type of tire is 75 feet when the car is going 40 miles per hour. In a test of 45 of these tires, the braking distance has a mean of 78 and a population standard deviation of 5.9 feet. Find the standardized test statistic and the corresponding p-value. Group of answer choices

Answer 1

Answer:

z=0.5084

p=0.2809

Step-by-step explanation:

Since number of tires tested for breaking distance is enough (>30), the standardized test statistic is calculated by the formula:

z=$\frac{X-M}{\frac{s}{\sqrt{N} }} }$ where

• X is the mean breaking distance in the sample (78)
• M is the mean breaking distance  (75)
• s is the standard deviation (5.9)
• N is the sample size

Putting the numbers in the formula:

z=$\frac{78-75}{\frac{5.9}{\sqrt{N} }} }$ =0.5084 and corresponding p value is:

p=0.28