Population Parameters

Which of the following answers is CORRECT for constructing a 98% confidence interval for a difference between two population proportions?

Is there any difference between population variances at 99% level of confidence if the 99% confidence interval (CI) for the ratio of population variance is (0.78, 1.56)? Verify.

• No difference because the 99% CI contains 1.

• Yes, there is a difference because the 99% CI does not contain 0.

• No difference because the upper limit of 99% CI is greater than the lower limit.

Suppose a 95% confidence interval for \mu_1-\mu_2 is (-2.13,1.48), what can you conclude?

• We are 95% confident that there is no difference between the population means.

• We are 95% confident that there is a difference between the population means.

Which statement is true?

• Statement A only

• Statement B only

• Statements A and B

• Neither A nor B

These symbols represent the mean and standard deviation for which of the following distributions?

• The Population

• The Sample

• The Sampling Distribution

What is a point estimate?

• average of sample values

• average of population values

• a single value that represents the unknown sample statistic

• a single value that represents the unknown population parameter

The scores of a random sample of 100 high school students on a standardized mathematics test in school A gave a mean of 78 and a standard deviation of 20. Find the 95% confidence interval estimate for the true average score in mathematics in this standardized test.

• 1.96 to 3.92

• 76 to 80

• 74.08 to 81.92

• 74.80 to 81.29

A random sample of 1000 college students in the United States is surveyed about how much money they spend on books per year, the mean amount is calculated. What is the population parameter?

• mean amount spent on textbooks by all college students in the US

• amount spent on textbooks by all college students

• mean amount spent on textbooks by all college students

• amount spent on textbooks by all college students in CA

A random sample of 1003 Mercy County voters is asked if they would vote for the incumbent governor. The percent responding yes is calculated. What is the population parameter?

• percentage of 1003 voters that would vote yes for the incumbent governor

• percentage of all voters in Mercy County that would vote yes for the incumbent governor

• percentage of all voters that voted yes for the mayor

• percentage of all voters that voted yes in the last election

What is a point estimate?

• Average of sample values

• Average of population values

• A single value that represents the unknown sample statistic.

• A single value that represents the unknown population parameter.