Ch 9 quiz complete solutions correct answers key

ch 9 quiz complete solutions correct answers key

Consider the following null and alternative hypotheses.

                                    Ho:  μ ≤ 67

                                    Ha:  μ > 67

These hypotheses _______________.

indicate a one-tailed test with a rejection area in the right tail

indicate a one-tailed test with a rejection area in the left tail

are not mutually exclusive

indicate a two-tailed test

3 points   

QUESTION 2

Suppose you are testing the null hypothesis that a population mean is greater than or equal to 60, against the alternative hypothesis that the population mean is less than 60.  The sample size is 64 and α = .05.  If the sample mean is 58 and the population standard deviation is 16, the observed z value is _______. (hint: you can use the Excel file for homework problem 9.7)

58

1

-8

8

-1

3 points   

QUESTION 3

A researcher is testing a hypothesis of a single mean. The critical z value for  α= .05 and a two‑tailed test is +1.96. The observed z value from sample data is ‑1.85. The decision made by the researcher based on this information is to _____ the null hypothesis. (hint: compare the observed z value to the values of the two tailed test)

change the alternate hypothesis into

fail to reject

reject

redefine

restate the null hypothesis

3 points   

QUESTION 4

In performing a hypothesis test where the null hypothesis is that the population mean is 23 against the alternative hypothesis that the population mean is not equal to 23, a random sample of 17 items is selected.  The sample mean is 24.6 and the sample standard deviation is 3.3.  It can be assumed that the population is normally distributed.  The degrees of freedom associated with this are _______.

17

2

1

15

16

3 points   

QUESTION 5

 In performing a hypothesis test where the null hypothesis is that the population mean is 4.8 against the alternative hypothesis that the population mean is not equal to 4.8, a random sample of 25 items is selected.  The sample mean is 4.1 and the sample standard deviation is 1.4.  It can be assumed that the population is normally distributed.  The level of significance is selected to be 0.10.  The table "t" value for this problem is _______. (hint: look up answer in table on p799 after calculating degrees of freedom and alpha)

1.318

3.227

2.797

2.492

1.711

3 points   

QUESTION 6

According to the following graphic , X and Y have _________.

strong negative correlation

virtually no correlation

weak negative correlation

strong positive correlation

moderate negative correlation

3 points   

QUESTION 7

 According to the following graphic, X and Y have _________.

moderate negative correlation

strong negative correlation

weak negative correlation

virtually no correlation

strong positive correlation

3 points   

QUESTION 8

In the regression equation, y = 49.56 + 0.97x, the slope is _______

49.56

1.00

-0.97

0.97

0.00

3 points   

QUESTION 9

In the regression equation, y = 54.78 + 1.45x, the intercept is _______

-1.45

1.45

54.78

-54.78

0.00

3 points   

QUESTION 10

The following data is to be used to construct a regression model: (hint: use INTERCEPT Excel function)

The value of the intercept is ________.

X

3

5

7

4

8

10

9

y

5

4

5

4

7

10

8

1.43

16.49

1.30

0.75

1.19