Statistical Based Inference

The average miles on a tank of gas for the Ford Explorer is 300 miles with a standard deviation of 22 miles. A consumer group feels the average is actually lower. They survey 40 vehicles and find the average miles per tank is 290 miles. At α = 0.05, test the consumer groups’ claim that the miles per tank is actually lower than 300 miles.

• There is enough evidence to reject the claim

• There is not enough evidence to reject the claim

• There is enough evidence to support the claim

• There is not enough evidence to support the claim

A cereal company claims the mean sodium content in

one serving of its cereal is no more than 230 mg. You

work for a national health service and are asked to test

this claim. You find that a random sample of 52

servings has a mean sodium content of 232 mg and a

standard deviation of 10 mg. At α = 0.05, do you have

enough evidence to reject the company’s claim?

• Reject Ho

• Reject Ha

• Fail to reject Ho

• Fail to reject Ha

The U.S. Department of Transportation reported that 77% of all fatally injured automobile drivers were intoxicated. A random sample of 27 records of automobile driver fatalities in Kit Carson County, Colorado, showed that 15 involved an intoxicated driver. Carson County believes their proportion is lower than the national average. Which p-value for this test?(use 5:1 prop Z test)

• p = 0.996

• p = 0.004

• p = 0.008

• p = -2.64

A seaside resort claims that 75% of the days during its peak season are clear. A consumer group feels this claim is too high so they examine a random sample of 150 days over the last two peak seasons, finding 105 clear days. At the 0.05 significance level, what conclusion can be made?(use 5:1 prop Z test)

• a. Reject H0 since the p-value is greater than α

• b. Reject H0 since the p-value is less than α

• c. Fail to reject H0 since the p-value is greater than α

• d. Fail to reject H0 since the p-value is less than α

• e. Accept H0 since the p-value is greater than α

The mean salary of federal government employees on the General Schedule is $59,593. The average salary of 30 randomly selected state employees who do similar work is $58,800 with $1500. At the 0.01 level of significance, can it be concluded that state employees earn on average less than federal employees?

• it can be concluded that state employees earn on average less than federal employees

• it can be concluded that state employees earn on average greater than federal employees

• it can be concluded that state employees income does not differ with federal employees

• it can be concluded that state employees income differs with federal employees

• there's sufficient evidence to conclude that the proportion of college students who recycle is greater than 70%

• there's insufficient evidence to conclude that the proportion of college students who recycle is greater than 70%

• can't conclude due to sampling error

Of U.S. residents traveling overseas, 47% were women and 53% were men. A random sample of 500 travelers on a large airline revealed that of those 500, 263 were women. Does this differ from the national percentage at the 0.05 level of significance?

• Does not differ from the national percentage

• Differs from the national percentage

• can't tell due to vague information

Which of the following refers to the characteristic or measure obtained by using the

data values from a sample.

• statistic

• parameter

• population

• test statistic

Which of the following refers to the characteristic or measure obtained by using all the

data values from a specific population.

• statistic

• parameter

• hypothesis test

• test statistic

• there's enough evidence to conclude that the sample mean differs from the national mean

• there's not enough evidence to conclude that the sample mean differs from the national mean

• can't tell due to incomplete information