This is a simple problem related to development of a contigency
table and then to conduct a chi square test to check for the
significance.
So let us develop the contigency table first .
Please note that we have taken the rows as experienced
/inexperienced and columns as approve and disapprove
respectively.
|
Approve |
Disapprove |
Total |
Experienced |
7 |
3 |
10 |
Inexperienced |
3 |
7 |
10 |
Total |
10 |
10 |
20 |
Thus we conclude that the approval rating is NOT dependent on
the experience of the participants. (Both variables are NOT related
to each other)
Other answers
from the contigency table.
1. 7 experienced teachers approved.
2. 3 inexperienced teachers approved.
3. The value of chi square is 3.20
4. The associated probability for chi square value of 3.2 is
0.0736
5. The test signifies that the null hypothesis cant be rejected
meaning that the two variables are NOT dpendent.
6. We conclude that the approval rating is NOT dependent on the
experience of the participants. (Both variables are NOT related to
each other)
The following cross tablulation have been provided. The row and column total have been calculated and they are shown below: Total 10 10 20 Column 2 Column 1 Row 1 Row 2 Total 10 10 The expected values are computed in terms of row and column totals. In fact, the formula is Eij-TG, where R, corresponds to the total sum of elements in row i, Ci corresponds to the total sum of elements in column j, and T is the grand total. The table below shows the calculations to obtain the table with expected values Total Column 2 10x15 1015 Column 1 1o105 1o105 10 Expected Values 10 Row 1 20 10 Row 2 20 20 10 Total Based on the observed and expected values, the squared distances can be computed according to the following formula: (E O)2/E. The table with squared distances is shown below: Column2 Column 1 3-5E0.8 50.8 Squared Distances Row 1 Row 2 50.8 = 0.8
The following null and alternative hypotheses need to be tested: HO: The two variables are independent H The two variables are dependent This corresponds to a Chi-Square test of independence. Reiection Recion Based on the information provided, the significance level is a 0.05, the number of degrees of freedom is df (2 1) x (2-1) 1, so then the rejection region for this test is R-[x: x2> 3.841) The Chi-Squared statistic is computed as follows: x®S(Qj E E,,)2=0.8 +0.8 +0.8 +0.8 = 3.2 Since it is observed that x-3.2 Sx rejected. 3.841, it is then concluded that the null hypothesis is not It is concluded that the null hypothesis Ho is not rejected. Therefore, there is NOT enough evidence to claim that the two variables are dependent, at the 0.05 significance level.