6.3 Confidence Intervals for Proportions

Front

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

Back

90%

Front

The symbol for the sample proportion is __________.

Back

p̂

Front

What happens to the confidence interval when only 250 out of 325 people show up for a survey with a 95% confidence level?

Back

It gets larger

Front

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?

Back

0.148 < p < 0.252

Front

95% confidence interval of the true proportion of women in Europe who use the Internet, given 35% of 750 users were women.

Back

0.316 < p < 0.384

Front

Interpret the 99% confidence interval (0.652, 0.868) for the proportion of students who went to the homecoming game.

Back

Based on this sample, I am 99% confident that the true proportion of people who went to the homecoming game this year is between 65.2% and 86.6%.

Front

Which confidence would result in a wider interval (assuming nothing else changed), 91% or 97%?

Back

97%, z* is larger for higher confidence intervals

Front

For a sample, the 95% confidence interval is (0.202, 0.482). What is the point estimate, p̂, of this sample?

Back

0.342

Front

For a sample, the 95% confidence interval is (0.202, 0.482).
What is the margin of error of this sample?

Back

0.14

Front

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?

Back

0.53