Assume event A is grade 80 , event B is interesting class, if you are given the
ID: 3394853 • Letter: A
Question
Assume event A is grade 80, event B is interesting class, if you are given the following contingency table. Even A and Event B are independent or dependent? The values in the table are number of students. Pick One: Independent ( ? ) or Dependent [ ( ? )
Grade
interested
not interested
Total
lower than 80
10
20
30
greater or equal to 80
40
10
50
Total
50
30
80
Grade
interested
not interested
Total
lower than 80
10
20
30
greater or equal to 80
40
10
50
Total
50
30
80
Explanation / Answer
Under null hypothesis Ho:event A is independent of event B. H1:event A is dependent of event B.
So we use chi-square independence of attribute test, so at 0.05 with (2-1)(2-1)=1 degrees of freedom is 3.841.
Then chi-squarecal=[(Oi-Ei)2/Ei]=17.4222. Here chi-squarecal>chi-squaretab, so we reject null hypothesis. Therefore, we accept H1:event A is dependent of event B.
Oi Ei (Oi-Ei)2/Ei 10 (30*50)/80=18.75 4.0833 20 (30*30)/80=11.25 6.8056 40 (50*50)/80=31.25 2.4500 10 (50*30)/80=18.75 4.0834 80 80 17.4222Related Questions
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