Question

Part 1) The U.S. Department of Transportation, National Highway Traffic Safety Administration, reported that 77% of all fatally injured automobile drivers were intoxicated. A random sample of 51 records of automobile driver fatalities in a certain county showed that 33 involved an intoxicated driver. Do these data indicate that the population proportion of driver fatalities related to alcohol is less than 77% in Kit Carson County? Use ? = 0.05.

(a) What is the level of significance?

(b) What is the value of the sample test statistic? (Round your answer to two decimal places.)


(c) Find the P-value of the test statistic. (Round your answer to four decimal places.)

Part 2) USA Today reported that about 47% of the general consumer population in the United States is loyal to the automobile manufacturer of their choice. Suppose Chevrolet did a study of a random sample of 1009 Chevrolet owners and found that 487 said they would buy another Chevrolet. Does this indicate that the population proportion of consumers loyal to Chevrolet is more than 47%? Use ? = 0.01.

(a) What is the level of significance?

(b)What is the value of the sample test statistic? (Round your answer to two decimal places.)


(c) Find the P-value of the test statistic. (Round your answer to four decimal places.)

Answer 1

Question 1:

a) The level of significance is already given in the problem statement as:

b) The sample proportion here is computed as: p = 33/51 = 0.6471

Therefore the test statistic here is computed as:

Therefore -2.09 is the test statistic value required here.

c) As this is a one tailed test, the p-value here is computed from the standard normal tables as:

p = P(Z < -2.09 ) = 0.0183

Therefore 0.0183 is the required p-value here.