Sample Z Test Means

A one sample t-test is conducted on Ho : μ = 81.6. The

sample has a sample mean = 84.1 , s = 3.1, n = 25, and α =

.01.

• 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

In performing a hypothesis test where the null

hypothesis is that the μ = 6.9. A random sample of 16

items is selected. The sample mean is 7.1 and the sample

standard deviation is 2.4. It can be assumed that the

population is normally distributed at α = .05.

• 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 fast food outlet claims that the mean waiting time in

line is less than 1.9 minutes. A random sample of 20

customers has a mean of 1.7 minutes with a standard

deviation of 0.8 minute. If α = 0.05, test the fast food

outlet's claim using P-values.

• 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 fast food outlet claims that the mean waiting time in

line is less than 3.5 minutes. A random sample of 20

customers has a mean of 3.7 minutes with a standard

deviation of 0.8 minute. If α = 0.05, test the fast food

outlet's claim.

• Reject Ho

• Reject Ha

• Fail to reject Ho

• Fail to reject Ha

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?

• There is enough evidence to reject claim

• There is not enough evidence to reject claim

• There is enough evidence to support claim

• There is not enough evidence to support claim

A car manufacturer advertises that its new subcompact models get 47 mpg. If μ is the mileage of these cars, what could be the null and alternate hypothesis if we wanted to check if the car's mpg is overrated? 

• H₀ = 47
  H_a = 47
• H₀ = 47
  H_a < 47
• H₀ = 47
  H_a > 47
• H₀ = 47
  H_a ≠ 47

An Air Force base mess hall has received a shipment of 10,000 gallon sized cans of cherries. The supplier claims that the average amount of liquid is 0.25 gallons per can. A government inspector took a random sample of 30 cans and found that the average liquid content to be 0.28 gallons per can with a standard deviation of 0.10. Does this indicate that the supplier's claim is too low? (Use a 5% level of significance)

• Fail to reject H₀ (z = 1.64)
• Reject H₀ (z = 2.56)
• Fail to reject H₀ (z = 1.64)
• Reject H₀ (z = 2.56)

In a research report, the results of a hypothesis test include the phrase " z=3.15, p<0.01". This means that the test failed to reject the null hypothesis.

• True
• False

Read the following question above.

• At the 1% level of significance, there's not enough evidence to support the claim (μ > 30) because we failed to reject H_o.

• At the 1% level of significance, there's enough evidence to support the claim (μ > 30) because H_o was rejected.