Questions from Statistics

Q: Find the critical value t0 for a left-tailed test with

Find the critical value t0 for a left-tailed test with α = 0.01 and n = 14.

Q: Find the critical value t0 for a right-tailed test with

Find the critical value t0 for a right-tailed test with α = 0.10 and n = 9.

Q: Find the critical values -t0 and t0 for a two-

Find the critical values -t0 and t0 for a two-tailed test with α = 0.05 and n = 16.

Q: An industry analyst says that the mean age of a used car

An industry analyst says that the mean age of a used car sold in the last 12 months is less than 4.1 years. A random sample of 25 used cars sold in the last 12 months has a mean age of 3.7 years and a...

Q: The company in Example 5 claims that the mean conductivity of the

The company in Example 5 claims that the mean conductivity of the river is 1890 milligrams per liter. The conductivity of a water sample is a measure of the total dissolved solids in the sample. You r...

Q: Find the critical value(s) and rejection region(s

Find the critical value(s) and rejection region(s) for the type of z-test with level of significance α. Include a graph with your answer. Two-tailed test, α = 0.02

Q: Another department of motor vehicles office claims that the mean wait time

Another department of motor vehicles office claims that the mean wait time is at most 18 minutes. A random sample of 12 people has a mean wait time of 15 minutes with a standard deviation of 2.2 minut...

Q: A researcher claims that more than 90% of U.S

A researcher claims that more than 90% of U.S. adults have access to a smartphone. In a random sample of 150 adults, 87% say they have access to a smartphone. At α = 0.01, is there enough evidence to...

Q: A researcher claims that 67% of U.S. adults

A researcher claims that 67% of U.S. adults believe that doctors prescribing antibiotics for viral infections for which antibiotics are not effective is a significant cause of drug-resistant superbugs...

Q: A bottling company claims that the variance of the amount of sports

A bottling company claims that the variance of the amount of sports drink in a 12-ounce bottle is no more than 0.40. A random sample of 31 bottles has a variance of 0.75. At α = 0.01, is there enough...