Confidence intervals quiz

Five questions on Confidence intervals. Answer all 5 to see your score. Questions are drawn from a bank of 15, so every attempt is different.

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Question 1 of 5

The critical value z* for 95% confidence is:

A poll of 1,000 has p-hat = 0.40. The 95% margin of error is about:

Increasing the confidence level from 95% to 99% makes the interval:

To halve the margin of error, the sample size must be:

With no prior estimate, sample size planning for a proportion uses p-hat =