In: Statistics and Probability
Willingness To Help |
Year in College |
|||
Freshman |
Sophomore |
Junior |
Senior |
|
Willing |
15 |
16 |
15 |
15 |
Unwilling |
15 |
14 |
5 |
5 |
Using these data, test the null hypothesis that willingness to help raise donations does not differ by year in school. Use a .05 confidence level for your test and be sure to report (a) the critical value of the test statistic, (b) the obtained value of the test statistic, (c) your decision about the null hypothesis, and (d) an interpretation of the meaning of your decision.
Step 1. We put the value in a table and add them up to give the
row total and col total and the grand total. As shown below.
Step 2 . We divide each value in the table with the grand total to
get the frequency precentage.
Step 3. We need to find the expected distribution which is done
below.
Step 4. We find the chi stat using the formula given below.
We sum all the chi value and get 5.56 and
Using chi table we find pvalue for the df = 6,
pvalue = 0.13494
Hypothesis
H0 : Willingness to help and Year in college are independent of
each other
H1 : Willingness to help and Year in college are not independent of
each other
Since the pvalue is greater than 0.05, we fail to reject the
null hypothesis.
We conclude Willingness to help and Year in college is independent
of each other