In: Statistics and Probability
Students in a high school were asked whether good grades, athletic ability, or popularity was most important to them. A two-way table separating the students by gender and by choice of most important factor (factor) is shown below:
Boys |
Girls |
||
Grades |
12 |
16 |
|
Popularity |
16 |
32 |
|
Sports |
30 |
14 |
|
100 |
For the data above, do the following
a)
Boys | Girls | Total | |
Grades | 12 | 16 | 28 |
Popularity | 16 | 32 | 48 |
Sports | 30 | 14 | 44 |
Total | 58 | 62 | 120 |
b)
Gender by factor percentages | |||
Boys | Girls | Total | |
Grades | 42.85714% | 57.14286% | 100% |
Popularity | 33.33333% | 66.66667% | 100% |
Sports | 68.18182% | 31.81818% | 100% |
c)
Factor by gender percentages | ||
Boys | Girls | |
Grades | 20.68966% | 25.80645% |
Popularity | 27.58621% | 51.6129% |
Sports | 51.72414% | 22.58065% |
Total | 100% | 100% |
d)
Chi square test of independence need to be done to test the association between gender and factor
e)
Where, r is the number of rows and c is the number of column in the table.
f)
The expected values are obtained using the formula,
Boys | Girls | Total | |
Grades | 28 | ||
Popularity | 48 | ||
Sports | 44 | ||
Total | 58 | 62 | 120 |
g)
The Chi-Square Value is obtained using the formula
Observed, | Expected, | |||
12 | 13.53333333 | -1.533 | 2.351 | 0.174 |
16 | 23.2 | -7.200 | 51.840 | 2.234 |
30 | 21.26666667 | 8.733 | 76.271 | 3.586 |
16 | 14.46666667 | 1.533 | 2.351 | 0.163 |
32 | 24.8 | 7.200 | 51.840 | 2.090 |
14 | 22.73333333 | -8.733 | 76.271 | 3.355 |
11.603 |
h)
i)
From the chi square table,
For significance level = 0.05 and degree of freedom = 2, the critical value is,
j)
Since the chi square value is greater than the critical value, It can be concluded that the null hypothesis is rejected at 5% significance level.
Hence both the variables factor and gender are dependent.