Question

Suppose 70 different survey organizations visit eastern Tennessee to estimate the average number of years of schooling completed among adults age 25 and over. Each organization surveys 400 people and reports a 90% confidence interval.

Of these 70 intervals, how many of these intervals would you expect to contain the true population average?

Answer 1

63 intervals would be expected to contain the true population average.

Explanation:

90% confidence interval:

Mean that we are 90% sure that the interval contains the true population mean. That is, 90% of the intervals are expected to contain the true population average.

Of these 70 intervals, how many of these intervals would you expect to contain the true population average?

Following the explained logic

0.9*70 = 63

63 intervals would be expected to contain the true population average.