Statistical Methods Quiz

What term is being used to describe a proposed explanation, assertion, or assumption about a population parameter or about the distribution of a random variable?

• statistic

• decision

• hypothesis

• probability

Which of the following would be an appropriate null hypothesis?

• The mean of a sample is equal to 80.

• The mean of a population is equal to 80.

• The mean of a population is not equal to 80.

• The mean of a population is greater than 80.

Which of the following must be used as the significance level if we want a lower possibility of correct decision?

• 1%

• 2%

• 5%

• 10%

In a one-tailed test, in which critical values below will the computed z of 2.312 falls in the non-rejection region?

• 2.228

• 1.533

• 1.383

• 2.354

When is a Type I error committed?

• We fail to reject a null hypothesis that is false.

• We reject a null hypothesis that is true.

• We fail to reject a null hypothesis that is true.

• We reject a null hypothesis that is false.

Which of the following is a Type I error?

• H0 is true; reject H0.

• H0 is false; reject H0.

• H0 is true; fail to reject H0.

• H0 is false; fail to reject H0.

If the computed z-value is 1.286 and the critical value is 1.383, which of the following statements could be true?

• It lies in the rejection region, H0 must be rejected.

• We fail to reject a null hypothesis that is true.

• We fail to reject a null hypothesis that is false.

• It lies in the rejection region, hence we fail to reject H0.

Using a left-tailed test, which of the following value of z will not fall in the rejection region where the critical value is – 1.638?

• – 1.706

• – 1.641

• – 1.639

• – 1.637

If the computed z-value is 1.915 and the critical value is 1.812, which of the following statements could be true?

• It lies in the non-rejection region, H0 must be rejected.

• It lies in the rejection region, H0 must be rejected.

• It lies in the rejection region, hence we fail to reject H0.

• It lies in the non-rejection region, hence we fail to reject H0.