Question

A study claims that the proportion of adults in the U.S. with rudimentary literary skills is 21%. A researcher believes the true percentage differs from this one that is published (Source: U.S. Department of Education). Which of the following demonstrates a Type I error?

A. Not rejecting H0: p = 0.21, when actually p = 0.21.

B. Rejecting H0: p = 0.21, when actually p = 0.21.

C. Rejecting H0: p = 0.21, when actually p is not equal to 0.21.

D. Not rejecting H0: p = 0.21, when actually p is not equal to 0.21.

Which correlation coefficient indicates a stronger correlation than +0.30?

A. 0.20

B. 100.0

C. -0.56

D. none of the above

The correlation coefficient r was computed to be -0.80. This indicates that

A. there is almost no relationship between the two variables

B. 80 percent of the variation in the independent variable is accounted for by the variation in the dependent variable.

C. the coefficient of determination is -0.20.

D. none of the above

The diameter of a spindle in a small motor is supposed to be 5 mm. If the spindle is either too small or too large, the motor will not work properly. The manufacturer measures the diameter in a sample of motors to determine whether the mean diameter has moved away from the target. What are the null and alternative hypotheses (H0 = null hypothesis and Ha = alternative hypothesis)?

A. H0: Mean= 5 and Ha: Mean is not equal to 5

B. H0: Mean = 5 and Ha: Mean <5

C. H0: Mean < 5 and Ha: Mean > 5

D. H0: Mean = 5 and Ha: Mean > 5

Answer 1

1)B. Rejecting H0: p = 0.21, when actually p = 0.21.

2) C. -0.56 as is absolute value is higher then 0.3

3) D. none of the above

4)A. H0: Mean= 5 and Ha: Mean is not equal to 5