In: Statistics and Probability
2. Below is some data on personality type (introverted or extroverted) and favourite colour. a) Run the appropriate test at a 5% significance level to determine if there is a relationship between these variables. (Be sure to state the hypotheses, test statistic, p-value, and conclusions.)
Run the standardized residuals. Provide the numbers and an interpretation.
Colours |
|||||
Red |
Yellow |
Green |
Blue |
||
Introvert personality |
20 |
6 |
30 |
44 |
|
Extrovert personality |
180 |
34 |
50 |
36 |
Ho: given two variable are independent
H1: Given two variables are not independent
Chi-Square Test of independence | |||||||
Observed Frequencies | |||||||
0 | |||||||
0 | red | yellow | green | blue | Total | ||
introvert | 20 | 6 | 30 | 44 | 100 | ||
extrovert | 180 | 34 | 50 | 36 | 300 | ||
Total | 200 | 40 | 80 | 80 | 400 | ||
Expected frequency of a cell = sum of row*sum of column / total sum | |||||||
Expected Frequencies | |||||||
red | yellow | green | blue | Total | |||
introvert | 200*100/400=50 | 40*100/400=10 | 80*100/400=20 | 80*100/400=20 | 100 | ||
extrovert | 200*300/400=150 | 40*300/400=30 | 80*300/400=60 | 80*300/400=60 | 300 | ||
Total | 200 | 40 | 80 | 80 | 400 | ||
(fo-fe)^2/fe | |||||||
introvert | 18.000 | 1.600 | 5.000 | 28.800 | |||
extrovert | 6.000 | 0.533 | 1.667 | 9.600 |
Chi-Square Test Statistic,χ² = Σ(fo-fe)^2/fe =
71.200
Level of Significance = 0.01
Number of Rows = 2
Number of Columns = 4
Degrees of Freedom=(#row - 1)(#column -1) = (2- 1 ) * ( 4- 1 )
= 3
p-Value = 0.0000 [Excel function:
=CHISQ.DIST.RT(χ²,df) ]
Decision: p-value < α , Reject Ho
conclusion: there is a relationship between these variables
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Please revert back in case of any doubt.
Please upvote. Thanks in advance.