Understanding Confidence Intervals for Population Proportions

This video tutorial explains how to determine a confidence interval for a population proportion. It covers the calculation of sample proportion, confidence level, alpha, and z-score. The tutorial also demonstrates how to calculate the margin of error and determine the confidence interval. Additionally, it provides instructions for using a TI-84 calculator to find confidence intervals, highlighting potential discrepancies due to rounding.

What is the sample size used to estimate the population proportion?

• 136

• 100

• 65

• 90

What is the decimal representation of the sample proportion given 65% successes?

• 0.50

• 0.90

• 0.65

• 0.35

What is the confidence level expressed as a decimal?

• 0.95

• 0.1

• 0.05

• 0.9

What is the z-score corresponding to a 90% confidence level?

• 1.645

• 1.96

• 1.28

• 2.33

How is the error bound calculated?

• Sample proportion divided by z-score

• Sample size divided by z-score

• Z-score multiplied by sample standard deviation

• Z-score multiplied by sample size

What is the formula for the sample standard deviation for the proportion?

• Square root of p prime times q prime divided by n

• Square root of n times p prime divided by q prime

• Square root of q prime times n divided by p prime

• Square root of p prime times n divided by q prime

What is the lower bound of the 90% confidence interval?

• 0.067

• 0.650

• 0.717

• 0.583

What is the upper bound of the 90% confidence interval?

• 0.717

• 0.067

• 0.583

• 0.650

What happens if you enter a decimal value for x in the calculator?

• The calculator accepts it as is

• The calculator rounds it up

• The calculator rounds it down

• The calculator gives an error

How does rounding x to a whole number affect the confidence interval?

• It slightly changes the interval

• It does not affect the interval

• It makes the interval narrower

• It makes the interval wider