A researcher Fran selects 100 subjects at random from a popu

A researcher, Fran, selects 100 subjects at random from a population, observes 50 have over $20 in cash in their wallet. She calculates three confidence intervals for the proportion that are expected to have over $20 in cash in their wallet. The confidence levels are 90%, 95%, and 99%, and the intervals are (0.371, 0.629), (0.402, 0.598), and (0.418, 0.582). Match each interval with its confidence level.

CI: (0.371, 0.629): ______

CI: (0.402, 0.598): __________

CI: (0.418, 0.582): ________

Solution

The higher is confidence leve, the wider gets the CI. thus the answers are:

CI: (0.371, 0.629): ______99%

CI: (0.402, 0.598): __________ 95%

CI: (0.418, 0.582): ________ 90%