Homework SourseAn industrial psychologist wishes to study the effect of mot
An industrial psychologist wishes to study the effect of motivation on sales in a particular firm. 24 new salespersons are randomly divided into two groups of 12. One group is paid an hourly rate and the other group is only paid a commission. The sales volume (in thousands of dollars) is recorded for all 24 salespersons during the first month with the firm. The sample mean and standard deviation for the group paid hourly are 227.6 and 13.84, respectively. The sample mean and standard deviation for the commission group are 247.9 and 21.59, respectively. The psychologist is interested in finding evidence at the .01 significance level to support the notion that the incentive posed by offering a commission yields greater average sales volume.
Give the value of the appropriate test statistic.
1.391
0.725
2.742
2.337
1.688
Which of the following correctly describes the p-value for the test statistic in #6?
p-value < .01
.01 < p-value < .025
.025 < p-value < .05
.05 < p-value < .10
p-value > .10
What critical value(s) would be used for comparison with the test statistic in #6?
1.330
2.552
-2.58, 2.58
-2.101, 2.101
1.734
What is the decision for the test statistic in #6?
Limburger cheese
Do not reject HA
Reject HA
Do not reject H0
Reject H0
Which of the following correctly describes the 98% confidence interval for the mean of the commission group minus the mean of the hourly group?
only values less than pi
only negative values
a) only positive values
only values less than cake
a) both negative and positive values
| a. | 1.391 | |
| b. | 0.725 | |
| c. | 2.742 | |
| d. | 2.337 | |
| e. | 1.688 |
Solution
An industrial psychologist wishes to study the effect of motivation on sales in a particular firm. 24 new salespersons are randomly divided into two groups of 12. One group is paid an hourly rate and the other group is only paid a commission. The sales volume (in thousands of dollars) is recorded for all 24 salespersons during the first month with the firm. The sample mean and standard deviation for the group paid hourly are 227.6 and 13.84, respectively. The sample mean and standard deviation for the commission group are 247.9 and 21.59, respectively. The psychologist is interested in finding evidence at the .01 significance level to support the notion that the incentive posed by offering a commission yields greater average sales volume.
Give the value of the appropriate test statistic.
a.
1.391
b.
0.725
c.
2.742
d.
2.337
e.
1.688
Which of the following correctly describes the p-value for the test statistic in #6?
a.
p-value < .01
b.
.01 < p-value < .025
c.
.025 < p-value < .05
d.
.05 < p-value < .10
e.
p-value > .10
What critical value(s) would be used for comparison with the test statistic in #6?
a.
1.330
b.
2.552
c.
-2.58, 2.58
d.
-2.101, 2.101
e.
1.734
What is the decision for the test statistic in #6?
a.
Limburger cheese
b.
Do not reject HA
c.
Reject HA
d.
Do not reject H0
e.
Reject H0
Which of the following correctly describes the 98% confidence interval for the mean of the commission group minus the mean of the hourly group?
a.
only values less than pi
b.
only negative values
c.
a) only positive values
d.
only values less than cake
e.
a) both negative and positive values
Pooled-Variance t Test for the Difference Between Two Means
(assumes equal population variances)
Data
Hypothesized Difference
0
Level of Significance
0.01
Population 1 Sample
Sample Size
12
Sample Mean
247.9
Sample Standard Deviation
21.59
Population 2 Sample
Sample Size
12
Sample Mean
227.6
Sample Standard Deviation
13.84
Intermediate Calculations
Population 1 Sample Degrees of Freedom
11
Population 2 Sample Degrees of Freedom
11
Total Degrees of Freedom
22
Pooled Variance
328.8369
Standard Error
7.4031
Difference in Sample Means
20.3000
t Test Statistic
2.7421
Upper-Tail Test
Upper Critical Value
2.5083
p-Value
0.0059
| a. | 1.391 | |
| b. | 0.725 | |
| c. | 2.742 | |
| d. | 2.337 | |
| e. | 1.688 |
