Testing a Claim About Variation Quiz - Statistics B U3L6
A simple random sample of 26 precipitation amounts has a standard deviation of 0.18. Find the test statistic, using a 0.01 significance level to test a claim that the standard deviation of all precipitation amounts is equal to 0.25.
12.960
In a survey, 30 random customers who purchased concessions at a movie theater listed the money they spent. The standard deviation was found to be $1.28. Find the critical value(s) needed to test a claim that the standard deviation of all individual money spent at the concession stand at movie theaters is equal to $1.45. Use a 0.05 significance level.
16.047, 45.722
The tests in a specific professor's statistic courses have scores with a standard deviation equal to 14.1. One of his last classes had 27 test scores with a standard deviation of 9.3. Use a 0.01 significance level to test the claim that this last class has less variation than previous classes. Find the critical value(s) needed to test the claim.
12.198
A simple random sample of 25 vitamin tablets is obtained, and the potassium content of each tablet is measured. The sample has a standard deviation of 3.7 mg. Use a 0.05 significance level to test the claim that the potassium content of vitamin tablets has a standard deviation equal to 3.2 mg. Find the critical value(s) needed to test the claim.
12.401, 39.364
The standard deviation of a simple random sample of 15 customer waiting times is found to be 4.8 minutes. Find the test statistic to test the claim that the standard deviation of all customer waiting times is greater than 3.5 minutes. Use a 0.01 significance level.
26.331
The standard deviation of a simple random sample of 40 calling times on a pay phone is found to be 2.6 minutes. Find the test statistic to test a claim that the standard deviation of all phone calls on a pay phone is less than 2.9 minutes. Use a 0.05 significance level.
31.348
A simple random sample of 20 women's hair lengths prior to entering a local hair salon is found to have a standard deviation of 1.2 inches. Use a 0.01 significance level to test the claim that the standard deviation of all women's hair lengths prior to entering the hair salon is greater than 1.0 in. Find the critical value(s) needed to test the claim.
36.191
A simple random sample of 8 women basketball player's weights has a standard deviation of 7.5 lb. Find the test statistic, using a 0.05 significance level, to test a claim that the standard deviation of all weights of women basketball players is less than 9 lb.
4.861
Eighty-one random people were surveyed about the time it takes to commute to work in the morning. The standard deviation of the simple random sample is 2.3 minutes. The test statistic for the sample is 105.8. Find the critical values, using a significance level of 0.10, needed to test a claim that the standard deviation of all commute times is equal to 2.0 minutes. State the initial conclusion.
60.391 and 101.879; because the test statistic is in the critical region, the test rejects the null hypothesis.
The playing time of 16 popular songs is found to have a standard deviation of 54.5 seconds. Use a 0.05 significance level to test the claim that the songs are from a population with a standard deviation less than one minute (60 seconds). State the initial and final conclusion.
Fail to reject the null hypothesis; there is not sufficient evidence to support the claim that the songs are from a population with a standard deviation less than one minute.
