Question

Television networks frequently run public opinion polls on issues of concern. One network conducted a scientific poll asking a question concerning the approval rating of the way President Obama was handling the Iraq War. At about the same time a second network ran an online poll using a very similar question. The results of the two polls are summarized in the following table.

Poll
Scientific Online
Approve 339 385
Disapprove 780 573
Total 1119 958

We would like to test to see if the two polls are consistent with respect to the proportion who approve of President Obama's handling of the war

If the x^2 test is used to test the null hypothesis, the expected cell count in the online poll for those who approve and that cell's contribution to the value of the test statistic are, respectively,

Group of answer choices

a. 390.1 and 7.70.
b. 333.9 and 6.78.
c. 390.1 and 6.69.
d. 333.9 and 7.81.
e. 362.0 and 1.46.

Answer 1

Option d

Explanation:

Given that television networks frequently run public opinion polls on issues of concern. One network conducted a scientific poll asking a question concerning the approval rating of the way President Obama was handling the Iraq War. At about the same time a second network ran an online poll using a very similar question.

Observed data is

Poll Scien Online total

approve 339 385 724

disapprove 780 573 1363

1119 958 2087

`H_0: Both scientific and online are consistent\\H_a: not consistent`

(Two tailed chi square test)

Let us find out expected and chi square

Expected = row total x column total/grand total

The cell count expected in the online poll for those who approve

=
`(724*968)/(2087) \\=333.94`

chi square = 7.81

Hence option d is right.