CW - 7.2

Decide whether reject Ho or fail to reject Ho given the following:
Claim: u < 23;  sample mean: 22;  standard deviation: 2.1; n= 50; a = 0.01

• reject Ho, at 1% level of significance, there is enough evidence to support the claim

• fail to reject Ho, at 1% level of significance, there is no enough evidence to reject the claim

• fail to reject Ho, at 1% level of significance, there is no enough evidence to support the claim

  
  

• reject Ho, at 1% level of significance, there is enough evidence to reject the claim

Find the p-value for a hypothesis test with the standardized test statistic z. Decide whether you reject Ho or fail to reject Ho.

two-tailed: z = -2.45; a = 0.05

• fail to reject Ho

• reject Ho

• none of these

Compute the value of the standardized test statistic (z-score). Round your answer to two decimal places.

You wish to test the claim that μ > 18 at a level of significance

of α=0.10 and are given sample statistics

n =45, sample mean = 19.12. Assume the population standard deviation is 2.8.

• z = 2.29

• z = 2.68

• z = 2.87

• z = 2.13

Test the claim that μ = 418, given that σ =90, α = 0.20 and the

sample mean = 415 and n = 75

• reject Ho, at 20% level of significance, there is enough evidence to support the claim

• fail to reject Ho, at 20% level of significance, there is not enough evidence to support the claim

• fail to reject Ho, at 20% level of significance, there is not enough evidence to reject the claim

• reject Ho, at 20% level of significance, there is enough evidence to reject the claim

Find the critical value and rejection region for the type of z-test with level of significance α.

left-tailed; a = 0.025

• -1.960

• 1.960

• -0.674

• 0.674

A fast food outlet claims that the mean waiting time in line is greater than 3.5 minutes. A random sample of 75 customers has a mean of 3.6 minutes with a population standard deviation of 0.8 minute. If α = 0.10, test the fast food outletʹs claim using critical values and rejection regions.

• fail to reject Ho, at 10% level of significance, there is not enough evidence to support the claim

• reject Ho, at 10% level of significance, there is enough evidence to reject the claim

• reject Ho, at 10% level of significance, there is enough evidence to support the claim

• fail to reject Ho, at 10% level of significance, there is not enough evidence to reject the claim

A fast food outlet claims that the mean serving time in line is 2 minutes. A random sample of 42 customers has a mean of 2.58 minutes with a population standard deviation of 1.2 minute. If α = 0.01, test the fast food outletʹs claim using critical values and rejection regions.

• fail to reject Ho, at 1% level of significance, there is not enough evidence to reject the claim

• reject Ho, at 1% level of significance, there is enough evidence to reject the claim

• reject Ho, at 1% level of significance, there is enough evidence to support the claim

• fail to reject Ho, at 1% level of significance, there is not enough evidence to support the claim

A manufacturer claims that the mean lifetime of its fluorescent bulbs is 1500 hours. A homeowner selects 40 bulbs and finds the mean lifetime to be 1480 hours with a population standard deviation of 80 hours. Test the manufacturerʹs claim. Use α = 0.20.

• reject Ho, at 20% level of significance, there is enough evidence to support the claim

• fail to reject Ho, at 20% level of significance, there is not enough evidence to reject the claim

• reject Ho, at 20% level of significance, there is enough evidence to reject the claim

• fail to reject Ho, at 20% level of significance, there is not enough evidence to support the claim

Find the critical value and rejection region for the type of z-test with level of significance α.

two-tailed; a = 0.05

•  $-1.645$  

•  $-1.960$  

•  $\pm1.645$  

•  $\pm1.960$  

Compute the value of the standardized test statistic (z-score). Round your answer to two decimal places.

You wish to test the claim that μ = 25 at a level of significance

of α=0.02 and are given sample statistics

n =45, sample mean = 26.1. Assume the population standard deviation is 4.21.

• z = 1.76

• z = -1.75

• z = 1.75

• z = -1.76