Answr the following questions 1 Last year 24 percent of the
Answr the following questions
1. Last year 24 percent of the sales and marketing managers at a computer software corporation earned less than $30,000. 15 percent earned at least $30,000 but less than $40,000. 19 percent earned at least $40,000 but less than $50,000, 36 percent earned at least $50,000 but less than $75,000, and 6 percent earned over $75,000. The personnel manager wants to see if there has been a recent change in the distribution of salaries. The following data represent this year\'s salary distribution for a random sample of sales and marketing executives at this company:
Salary
Current Number
Less than $30,000
27
$30,000 and < $40,000
30
$40,000 and < $50,000
30
$50,000 and < $75,000
72
$75,000 and over
57
At the .01 level of significance, check to see if there has been a change in the population distribution of salaries at this company.
b. Write the null hypothesis.
b. Write the alternate hypothesis.
c. What is the level of significance?
d. What test must you use to answer this question?
e.What are the degrees of freedom?
f. What is the critical region?
g. State the Decision Rule
h. What is the test ratio?
i. . State the Statistical Decision
2. The sales manager of the Tackey Toy Company has hired a researcher to gather and evaluate opinion data about Tackey products from people in different parts of the country. The researcher randomly sampled toy buyers in each of four regions. Each respondent was first asked if he or she had ever heard of Tackey Toys. Those who were familiar with Tackey products were then asked if Tackey toys were competitively priced or if they were overpriced. The following sample results were obtained:
Geographic Region
Unfamiliar with Tackey Toys
Toys are Priced Competitively
Toys are overpriced
Total
New England
64
28
106
198
West Coast
84
42
76
202
Gulf Coast
56
14
130
200
Midwest
60
20
120
200
Total
264
104
432
800
At the .01 level of significance, check to see if there is no regional differences in the way the population of toy buyers responded to the Tackey survey.
a. Write the null hypothesis.
b. Write the alternate hypothesis.
c. What is the level of significance?
d. What test must you use to answer this question?
e. What are the degrees of freedom?
f. What is the critical region?
g. State the Decision Rule.
h. What is the test ratio?
i. State the Statistical Decision:
| Salary | Current Number |
| Less than $30,000 | 27 |
| $30,000 and < $40,000 | 30 |
| $40,000 and < $50,000 | 30 |
| $50,000 and < $75,000 | 72 |
| $75,000 and over | 57 |
Solution
H0: Distribution is as per last year
Ha: Distribution is not as per last year
Alpha = sign. level = 0.01
d) Chi square test can be used
e) df = 5-1 =4
Prepare contingency table as follows:
p value for chi square 165.1312 for df 4 < 0.00001. The result is significant at p < 0.01.
Hence there is change.
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H0: There is no difference between regions for toy purchases
Ha: there is difference
c) sign. level =0.01
d) chi square
e) (r-1)(c-1) = 3(2) = 6
Prepare contingency table for the rest.
chi-square = 39.0
degrees of freedom = 6
probability = 0.000
As p <0.01, reject null hypothesis.
It is statistically evident that there is regional differences in the way the population of toy buyers responded to the Tackey survey.
| Salary | Current no | Percent | Expected no | Chi square |
| <30000 | 27 | 24 | 51.84 | 11.9025 |
| 30000-40000 | 30 | 15 | 32.4 | 0.177778 |
| 30 | 19 | 41.04 | 2.969825 | |
| 72 | 36 | 77.76 | 0.426667 | |
| 57 | 6 | 12.96 | 149.6544 | |
| 216 | 100 | 216 | 165.1312 |



