Stats Final Review

nYou measure the heights of a random sample of 400 high school sophomore males in a Midwestern state. The sample mean is   ̅̅x= 66.2 inches. Suppose that the heights of all high school sophomore males follow a normal distribution with unknown mean   and standard deviation  σ= 4.1 inches. A 90% confidence interval is used. What is the critical value?

• 1.645

• 1.96

• 1.711

• 1.708

Tags

CCSS.HSS.ID.A.4

You measure the heights of a random sample of 400 high school sophomore males in a Midwestern state. The sample mean is   ̅̅x= 66.2 inches. Suppose that the heights of all high school sophomore males follow a normal distribution with unknown mean   and standard deviation  σ= 4.1 inches. A 90% confidence interval is used. What would produce a confidence interval with a smaller margin of error?

• increase sample size

• Increase confidence level

• Decrease sample size

• Increase standard deviation

Tags

CCSS.HSS.IC.B.4

In the group of 345 children surveyed, the sample mean was 11.3 and the standard deviation was 1.8. Find the 95% confidence interval for this data in the form of:

statistic ±critical value ∙margin of error 

Tags

CCSS.HSS.IC.B.4

Felix measured the thickness of 25 randomly selected points on one of the parts of a car to see if it was painted properly. His sample had a mean thickness of 148 and a standard deviation of 3.3. A 90% confidence for the average thickness of the whole car is:

• A

• B

• C

• D

Tags

CCSS.HSS.IC.B.4

Gallup is a company that carries out daily opinion polls on a variety of topics. In a recent daily poll of 1000, 334 said they were engaged at work. Establish a 98% confidence interval for the population proportion of people who are engaged at work.

• A

• B

• C

• D

Tags

CCSS.HSS.IC.B.4

The t-distributions have similarities to the standard normal distribution, but:

• t-distributions are not quite symmetrical

• t-distributions are centered at (n-1)

• the spread is greater

• t-distributions have an unknown shape

If we have a mean of 250, s = 100, and n = 16. And we are trying to see if there is evidence the population mean is greater than 200. To do this we test the hypothesis:

H0: μ = 200

Ha: μ > 200

What is the p-value?

• larger than 0.10

• between 0.01 and 0.05

• between 0.05 and 0.10

• below 0.01

An SRS of 100 was taken and fifty nine were considered a success. If we were conducting a 95% confidence interval and wanted to halve the margin of error. To do this, the sample size should be changed to:

• n = 50

• n = 100

• n = 200

• n = 400

An SRS of 150 was taken and fifty nine were considered a success. If we were to construct a 95% confidence interval to estimate the population proportion of success. Which of the following would determine the margin of error:

• 
• 
• 
• 

Tags

CCSS.HSS.IC.B.4

An SRS of 150 was taken and fifty nine were considered a success. If we are testing the hypothesis:

H₀ : p = 0.40

H_a : p < 0.40

What is the test statistic for this test?

• 
• 
• 
•