Multiple choice: Select the best answer for Exercises 49 to 52. A newspaper reporter

Problem 52

Multiple choice: Select the best answer for Exercises 49 to 52. A newspaper reporter asked an SRS of 100 residents in a large city for their opinion about the mayor's job performance. Using the results from the sample, the C% confidence interval for the proportion of all residents in the city who approve of the mayor's job performance is 0.565 to 0.695. What is the value of C?

(a) 82

(b) 86

(c) 90

(d) 95

(e) 99

                                                               Step by Step Solution

Step 1 of 2

Given,

Sample size,

Confidence interval = 0.565, 0.695

The sample proportion iss at the middle of the confidence interval, ie;

Boundaries of the confidence interval is,

Substituting the values,

Subtract 0.63 from both side:

By dividing both sides by  , we get:

 ?

Now, we can say that the confidence interval is the probability that the sample proportion is between  = 1.35and   = -1.35.