In: Statistics and Probability
Problem ONE:
The Contingency Table below shows the results of 400 randomly selected University of Toledo students to determine if there was any significant relationship between their attitude toward Donald Trump and their college major..
Attitude Toward President Trump
Major Field Approve Neutral Dislike
Nursing/Health 30 20 50
Liberal Arts/Social Science 2 20 68
Engineering 50 40 10
Business 58 50 2
a………If there is no relationship between one’s major and one’s attitude toward Trump, how many engineers would you expect to approve of Donald Trump?
b……..If you used a Chi-Square Test to analyze this data, how many Degrees of Freedom would this model have?
c……..True or False:
At α = 0.01, there is a significant relationship between attitude and major field.
d……. What is the value of the Chi Square test statistic? ANSWERS
a)
b)
c)
d)
(a)
P(Engineering AND Approve) = 140 X 100/400 = 35
So,
Answer is:
35
(b)
Degrees of Freedom = (r - 1) X (c - 1)
= (4 - 1) X (3 - 1) = 6
So,
Answer is:
6
(c)
Observed Frequencies are given as follows:
Major field | Approve | Neutral | Dislike | Total |
Nursing/ Health | 30 | 20 | 50 | 100 |
Liberal arts/Social science | 2 | 20 | 68 | 90 |
Engineering | 50 | 40 | 10 | 100 |
Business | 58 | 50 | 2 | 110 |
Total | 140 | 130 | 130 | 400 |
The Expected Frequencies are got as follows:
Observed Frequencies are given as follows:
Major field | Approve | Neutral | Dislike | Total |
Nursing/ Health | 140X100/400=35 | 32.5 | 32.5 | 100 |
Liberal arts/Social science | 31.5 | 29.25 | 29.25 | 90 |
Engineering | 35 | 32.5 | 32.5 | 100 |
Business | 38.5 | 35.75 | 35.75 | 110 |
Total | 140 | 130 | 130 | 400 |
The Test Statistic got as follows:
Observed Frequency (O) | Expected frequency (E) | (O -E)2/E |
30 | 35 | 0.71 |
20 | 32.5 | 4.81 |
50 | 32.5 | 9.42 |
2 | 31.5 | 27.63 |
20 | 29.25 | 2.93 |
68 | 29.25 | 51.34 |
50 | 35 | 6.43 |
40 | 32.5 | 1.73 |
10 | 32.5 | 15.58 |
58 | 38.5 | 9.88 |
50 | 35.75 | 5.68 |
2 | 35.75 | 31.86 |
Total = = | 167.9876 |
So,
Test statistic = 167.9876
By Technology, p- value < 0.00001
Since p - value is less than = 0.01, the difference is significant. Reject null hypothesis.
Conclusion:
The data support the claim that there is significant relationship between attitude and major field.
So,
Correct option:
True
(d)
Value of Chi square test statistic is 167.9876
Thus, answers to questions:
(a) 35
(b) 6
(c) True
(d) 167.9876