Quiz about Confidence Intervals Review

Question 1

When interpreting the confidence interval, make sure that you are describing the

Accepted Answer

parameter

Answer

statistic

Question 2

Which of the following is an example of an interval estimate?

Accepted Answer

confidence interval

Answer

point estimate

Answer

critical value

Answer

statistic

Question 3

A __________ gives an interval of plausible values for the _____________.

Accepted Answer

confidence interval, parameter

Answer

confidence interval, statistic

Answer

point estimate, parameter

Answer

point estimate, statistic

Question 4

Complete the equation:
point estimate +/- _____

Accepted Answer

margin of error

Answer

standard deviation

Answer

critical value

Answer

confidence level

Question 5

Suppose that $51,759 was the median income for all households in 2012. Does the interval ($51,484, $52,394) provide convincing evidence that the median household income increased in 2013?

Accepted Answer

No

Answer

Yes

Question 6

What is the format for interpreting a confidence interval?

Accepted Answer

We are C% confident that the interval from ___ to ___ captures the [parameter in context].

Answer

The interval from ___ to ___ captures the true mean in context.

Answer

C% of samples of the same size taken from the same population will capture the parameter in question

Answer

There is convincing evidence that C% gives the interval (___, ___) capturing the parameter in question.

Question 7

Is there bias?
A four company wants to know what percent of local households bake at least twice a week. A company representative calls 500 randomly selected households during the daytime.

Accepted Answer

Yes

Answer

No

Question 8

Increasing the sample size __________ the confidence interval.

Accepted Answer

decreases

Answer

increases

Answer

does not affect

Answer

there is not enough evidence to determine the answer

Question 9

What can you do to reduce the margin of error?

Accepted Answer

increase sample size

Answer

increase the confidence level

Answer

decrease the confidence level

Answer

decrease sample size

Question 10

Are the conditions met?
A recent poll of 738 randomly selected customers of a major US cell-phone carrier found that 170 of them had walked into something or someone while talking on a cell phone.

Accepted Answer

Yes

Answer

No

Answer

There is not enough data to determine.

Question 11

What is the critical value z* for a 99% confidence interval?

Accepted Answer

2.58

Answer

-2.58

Answer

1.96

Answer

-1.64

Question 12

Given the interval (1.2, 1.8), what is the point estimate and the margin of error?

Accepted Answer

1.5, 0.3

Answer

1.5, 0.6

Answer

1.2, 0.3

Answer

1.2, 0.6

Question 13

In a recent poll of 803 randomly selected baseball fans in Connecticut, 44% said their favorite team was the Yankees. If researchers wanted to reduce the margin of error to at most 2%, how many baseball fans do they have to randomly select?

Accepted Answer

2367

Answer

1564

Answer

803

Answer

3170

Question 14

What critical value t* is used in constructing a 99% confidence interval based on n = 12 randomly selected observations.

Accepted Answer

3.106

Answer

3.055

Answer

2.58

Answer

1.96

Question 15

The Large Counts condition is met by using what equation?

Accepted Answer

n >/ 30

Answer

n(p-hat)

Answer

n > 10

Answer

n(1-p-hat)

Question 16

Construct a 90% confidence interval of a random sample size of 19 cows with a mean of 155.526 and a standard deviation of 19.993.

Accepted Answer

(147.57, 163.48)

Answer

(146.54, 164.52)

Answer

(147.59, 163.46)

Answer

(143.69, 167.36)

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