Confidence Intervals for One Sample Z Proportions

What is the margin of error of this sample?

• 0.28

• 0.14

• 0.342

• 0.684

A random sample of 100 WHS students found that 53 of them were in possession of a pencil. What is the p-hat for this sample?

• 0.53

• 0.5

• 0.47

• 1

Identify the confidence interval used in the figure below if each shaded area is equal to 0.05.

• 90%

• 95%

• 98%

• 99%

Find the critical value, z*, for 91% confidence.

• 70

• 1.34

• 0.18

• -1.34

A survey of 800 women shoppers found that 17% of them shop on impulse.  What is the 98% confidence interval for the true proportion of women shoppers who shop on impulse? 

• 0.148 < p < 0.192

• 0.136 < p < 0.204

• 0.144 < p < 0.196

• 0.139 < p < 0.201

The confidence level of an interval estimate of a parameter is the probability that the interval estimate will contain the parameter.

• True

• False

Find the value of z_c for a 90% confidence interval.

• -1.96 

• 1.645

• 1.440

• -1.598

A sample of 400 racing cars showed that 80 cars cost over $700,000. What is the 99% confidence interval of the true proportion of cars costing over $700,000?

• 0.001 < p < 0.005

• 0.566 < p < 0.693

• 0.148 < p < 0.252

• 0.023 < p < 0.045

A recent study of 750 Internet users in Europe found that 35% of Internet users were women.  What is the 95% confidence interval of the true proportion of women in Europe who use the Internet? 

• 0.321 < p < 0.379

• 0.316 < p < 0.384

• 0.309 < p < 0.391

• 0.305 < p < 0.395

The symbol for the sample proportion is __________.

• z*

• p̂

• E

• p