Confidence Intervals 1

Question 1

Find a 98% confidence interval given: Sample Size: 32; Sample Mean: 78.25; Population δ: 37.50.

Accepted Answer

(62.81, 93.69)

Question 2

Which of the following is not a point estimate of a population?

Accepted Answer

Sample Road

Question 3

The probability that the interval estimate will include the population parameter (mean, etc).

Accepted Answer

The confidence level

Question 4

Given a random sample, A 90% confidence interval means that there is a 90% probability that the

Accepted Answer

given confidence interval will contain the true parameter

Question 5

Find a 90% confidence interval given: Sample Size: 32; Sample Mean: 78.25; Population δ: 37.50.

Accepted Answer

(67.38, 89.12)

Question 6

Find the minimum sample size needed for a 95% confidence interval: E = 8; n = 32; δ = 37.50 .

Accepted Answer

85

Question 7

A given confidence interval tells us how good of an estimate the _______________ is

Accepted Answer

sample

Question 8

Find the minimum sample size needed for a 99% confidence interval: E = 8; n = 32; δ = 37.50 .

Accepted Answer

146

Question 9

Find the minimum sample size needed for a 98% confidence interval: E = 8; n = 32; δ = 37.50 .

Accepted Answer

120

Question 10

To find the 99% confidence level, use the Bell Curve to occupy the middle 99%, thus 99.5% of

Accepted Answer

the graph will be to the left: find the z-value for 0.9950

Question 11

For small sample sizes, sample means will follow ___________

Accepted Answer

the Student's t-distribution

Question 12

If under the bell curve, 5% of the area is to the right & 95% of the area is to the left,

Accepted Answer

then we have a 90% confidence level

Question 13

The z-score corresponding to a 95% confidence level.

Accepted Answer

1.96

Question 14

To find the 98% confidence level, use the Bell Curve to occupy the middle 98%, thus 99% of

Accepted Answer

the graph will be to the left: find the z-value for 0.9900

Question 15

A statistic is a numerical description of a(n) _________

Accepted Answer

sample

Question 16

A 90% confidence interval has a

Accepted Answer

10% significance level

Question 17

If under the bell curve, 1% of the area is to the right & 99% of the area is to the left,

Accepted Answer

then we have a 98% confidence level

Question 18

A point estimate is a single value that best describes _____________

Accepted Answer

the population of interest

Question 19

The width of the confidence interval is determine by ____________

Accepted Answer

the margin of error

Question 20

The z-score corresponding to a 90% confidence level.

Accepted Answer

1.645

Question 21

When the sample measurement is different from the population measurement.

Accepted Answer

the sampling error

Question 22

Which of the following provides a range of values that best describes a population?

Accepted Answer

An interval estimate

Question 23

One role of statistics is to gather information from a sample and use that information to make

Accepted Answer

a statement about the population from which it was chosen

Question 24

A 95% confidence interval has a

Accepted Answer

5% significance level

Question 25

Which of the following describes a large sample of size n ?

Accepted Answer

n ≥ 30

Question 26

Find a 99% confidence interval given: Sample Size: 32; Sample Mean: 78.25; Population δ: 37.50.

Accepted Answer

(61.18, 95.32)

Question 27

A 98% confidence interval has a

Accepted Answer

2% significance level

Question 28

If under the bell curve, 0.5% of the area is to the right & 99.5% of the area is to the left,

Accepted Answer

then we have a 99% confidence level

Question 29

If under the bell curve, 2.5% of the area is to the right & 97.5% of the area is to the left,

Accepted Answer

then we have a 95% confidence level

Question 30

The critical z-score × The standard error of the mean

Accepted Answer

The formula for finding the margin of error

Question 31

The probability that any given confidence interval will not contain the true parameter is ____

Accepted Answer

the level of significance, α

Question 32

A parameter is a numerical description of a(n) _________

Accepted Answer

population

Question 33

The probability that the interval estimate will include the population parameter is the _______

Accepted Answer

confidence level

Question 34

For large sample sizes, sample means will follow ___________

Accepted Answer

the normal probability distribution

Question 35

If you increase the sample size, then ______

Accepted Answer

the confidence interval becomes narrower and more precise

Question 36

A 99% confidence interval has a

Accepted Answer

1% significance level

Question 37

The mean ± The critical z-score × The standard error of the mean

Accepted Answer

The formula for constructing the confidence interval

Question 38

If you increase the confidence level, then ______

Accepted Answer

the confidence interval becomes wider and less precise

Question 39

Find the minimum sample size needed for a 90% confidence interval: E = 8; n = 32; δ = 37.50 .

Accepted Answer

60

Question 40

To find the 90% confidence level, use the Bell Curve to occupy the middle 90%, thus 95% of

Accepted Answer

the graph will be to the left: find the z-value for 0.9500

Question 41

The z-score corresponding to a 98% confidence level.

Accepted Answer

2.33

Question 42

To find the 95% confidence level, use the Bell Curve to occupy the middle 95%, thus 97.5% of

Accepted Answer

the graph will be to the left: find the z-value for 0.9750

Question 43

Find a 95% confidence interval given: Sample Size: 32; Sample Mean: 78.25; Population δ: 37.50.

Accepted Answer

(65.26, 91.24)

Question 44

The probability for the confidence interval is _________

Accepted Answer

the complement to the significance level

Question 45

The standard deviation (δ) divided by the square root of the sample size (n) is _______

Accepted Answer

the standard error of the mean

Question 46

The z-score corresponding to a 99% confidence level.

Accepted Answer

2.575

Confidence Intervals 1

Questions 46

Confidence Intervals 1

Questions 46