Prepare answers to the following assignments from the e-text, *Applied Statistics in Business and Economics*, by Doane and Seward:

Chapter 15 - Chapter Exercises **15.18**, **15.22**, **15.24**, and **15.28**

**15.18**

**Sixty-four students in an introductory college economics class were asked how many credits they had earned in college, and how certain they were about their choice of major. Research question: At Î± = .01, is the degree of certainty independent of credits earned?**

**Credits Earned Very Uncertain Somewhat Certain Very Certain Row Total 0-9 12 8 3 23 10-59 8 4 10 22 60 or more 1 7 11 19 Col Total 21 19 24 64**

H0: The two factors are independent HA: There is a relationship between the two factors. | |||||||

Level of Significance: ï¡ = 1% | |||||||

Decision Rule: Reject the null hypothesis if p-value < 0.01 | |||||||

Chi-square Contingency Table Test for Independence | |||||||

Very Uncertain | Somewhat Certain | Very Certain | Total | ||||

0-9 | Observed | 12 | 8 | 3 | 23 | ||

Expected | 7.55 | 6.83 | 8.63 | 23.00 | |||

O - E | 4.45 | 1.17 | -5.63 | 0.00 | |||

(O - E)Â² / E | 2.63 | 0.20 | 3.67 | 6.50 | |||

Oct-59 | Observed | 8 | 4 | 10 | 22 | ||

Expected | 7.22 | 6.53 | 8.25 | 22.00 | |||

O - E | 0.78 | -2.53 | 1.75 | 0.00 | |||

(O - E)Â² / E | 0.08 | 0.98 | 0.37 | 1.44 | |||

60 or more | Observed | 1 | 7 | 11 | 19 | ||

Expected | 6.23 | 5.64 | 7.13 | 19.00 | |||

O - E | -5.23 | 1.36 | 3.88 | 0.00 | |||

(O - E)Â² / E | 4.39 | 0.33 | 2.11 | 6.83 | |||

Total | Observed | 21 | 19 | 24 | 64 | ||

Expected | 21.00 | 19.00 | 24.00 | 64.00 | |||

O - E | 0.00 | 0.00 | 0.00 | 0.00 | |||

(O - E)Â² / E | 7.11 | 1.51 | 6.15 | 14.76 | |||

14.76 | chi-square | ||||||

4 | df | ||||||

.0052 | p-value | ||||||

Since the p-value is less than 0.01, the null hypothesis is rejected. | |||||||

Therefore, there is sufficient evidence to conclude at 5% level of significance that | |||||||

the degree of certainty... |