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Sample Size
"Critical" Information
Confidence
Confidence Interval Mix 'n Match
Pick Me!
100

What year was Ms. Murray born?

1998

100
What happens to the width of the intervals when you increase your confidence level?
they get wider
100
For a one-sample proportion confidence interval, the middle value of the interval is equal to what?
p-hat
100

An organization reports that a 90% confidence interval for the true mean grade is 84 to 90. What is the point estimate from this interval?

87

100

In a sample survey taken of 527 residents of a given community, 167 of them indicated that they shop at the local mall at least once per month. What is the point estimate from this sample?

A) 167

B) 527

C) 0.5

D) 0.32

D) 0.32

200
What happens to the WIDTH of the intervals when you INCREASE your sample size?
The intervals become narrower.
200

What happens to the width of the intervals when you increase Margin of Error?

wider

200
What is the formula for a one-sample proportion confidence interval?
p-hat +/- z*sqrt(p-hat*q-hat/n)
200

An organization reports that a 90% confidence interval for the true mean grade is 83 to 96. What is the margin of error from this interval?

6.5

200
The critical value for a 99.7% confidence interval for p is: (A) 1 (B) 1.96 (C) 2 (D) 2.78 (E) 3
(E)
300

From earlier studies, it is believed that the percentage of students that pack their lunch every day is 45%. What is the minimum sample size that will create a margin of error of ±4% with 95% confidence?

595

300

What is the z* for an 90% confidence interval?

1.645

300

What does n(p-hat) and n(1- p-hat) have to be greater than?

10

300

A simple random sample of 300 high school seniors in a particular city is taken, and it is found that 250 of those students do not take the bus to school. Construct a 90% confidence interval for this parameter. Skip the conditions.

(.798, .868)

300

The confidence that we feel about a 90% confidence interval comes from the fact that

(A)there is a 90% chance that the population parameter is contained in the confidence interval

(B)there is a 90% chance that the sample statistic is contained in the confidence interval.

(C)90% of confidence intervals constructed around a sample statistic will contain the population parameter.

(D)the terms of confidence and probability are interchangeable.

(E)the concepts of confidence and probability are synonymous.

(C)

400
What sample size should be taken to estimate p within .05 at a 95% level?
385
400

What is the z* for an 84% confidence interval

1.405

400

What are three things you need to include in your sentence when interpreting confidence interval?

Confidence Level

Context

The interval

400

A simple random sample of 300 high school seniors in a particular city is taken, and it is found that 250 of those students do not take the bus to school. What is the Margin of Error for 90% confidence interval? skip the conditions.

.035

400

Which of the following is NOT true about constructing confidence intervals?

(A)The center of the confidence interval is the population parameter.

(B) One of the values that affects the width of a confidence interval is the sample size.

(C)If the value of the population parameter is known, it is irrelevant to calculate a confidence interval for it.

(D)The value of the level of confidence will affect the width of a confidence interval.

(A)