Chapter 8, Problem T8.6SPT

To determine

To explain which of the conditions for calculating a confidence interval for the population proportion.

Answer to Problem T8.6SPT

Only I.

Explanation of Solution

Given:

  $n=100$

  $x=70$

The condition of random selection is not satisfied because they were not chosen the random sample. They just took an answered people. Therefore, random sample condition not satisfied.

The sample should be less than 10% of the population. Here, 100 is less than 10% of the large audience set. Hence, this condition met.

The last condition is, number of success and failure must be $\ge 10$ . Therefore, number of successes =70 and number failures = 100-70 $\ge 10$ which is met. Hence, this condition is met.

Only condition of random not satisfied.