Confidence Intervals

Question 1

The product of which two quantities gives the margin of error for a 95% confidence interval?

Answer 1

(critical value)×(standard error)

Question 2

Holding other quantities fixed, increasing the level of confidence has what impact on the width of the confidence interval?

Answer 2

The width of the interval increases.

Question 3

Holding other quantities fixed, increasing the level of confidence has what impact on the margin of error of the confidence interval?

Answer 3

The margin of error increases.

Question 4

Holding other quantities fixed, decreasing the level of confidence has what impact on the width of the confidence interval?

Answer 4

The width is decreased.

Question 5

Holding other quantities fixed, decreasing the level of confidence has what impact on the magnitude of the margin of error?

Answer 5

The margin of error decreases.

Question 6

Holding other quantities fixed, increasing the sample size has what impact on the width of the confidence interval?

Answer 6

The interval becomes narrower.

Question 7

Holding other quantities fixed, decreasing the sample size has what impact on the width of the confidence interval?

Answer 7

The confidence interval expands.

Question 8

If the following measurements are drawn from a population which follows a normal distribution, what would be the best point estimate for the true mean?

3, 3, 6

Answer 8

x-bar = 4

Question 9

If the following measurements are drawn from a population which follows a normal distribution, in order to have a valid 95% confidence ishape of X?
3, 3, 6

Answer 9

X, the population being used to make the inference, must have a shape that follows a normal distribution.

Question 10

Given the following 95% confidence interval for the true proportion of UF students that are in love with Tim Tebow, what is the margin of error?

(0.28, 0.42)

Answer 10

0.07

Question 11

Given the following 95% confidence interval for the true proportion of UF students that are in love with Tim Tebow, what is the point estimate?

(0.28, 0.42)

Answer 11

p-hat = 0.35

Question 12

Given the following 95% confidence interval for the true proportion of UF students that are still in love with Tim Tebow, in context, what is the best interpretation?

(0.28, 0.42)

Answer 12

We are 95% confidenct the true proportion of UF students who are still in love with Tim Tebow is between 28% and 42%.

Question 13

Given the following 68% confidence interval for the true mean number of Pringles in a single Pringles canister, in context, what is the best interpretation?

(98, 102)

Answer 13

We are 68% confident the true mean number of Pringles in a canister is bwtween 98 and 102.

Question 14

What is the name of theorem whose results make introductory statistical methods valid?

Answer 14

THE CENTRAL LIMIT THEOREM.

Question 15

In words, how can the standard error of the means be calculated for a 99.7% confidence interval to estimate the true mean?

Answer 15

Take the population standard deviation and divide by the square root of the sample size.

Question 16

In words, how can the standard error of the means be calculated for a 95% confidence interval to estimate the true mean?

Answer 16

Take sigma and divide it by square root of the sample size.

Question 17

In words, how can the standard error of the means be calculated for a 68% confidence interval to estimate the true mean?

Answer 17

Take the population standard deviation and divide it by the sample size.

Question 18

For some binomial population X, assuming the central limit theorem to holds, what would follow a normal distribution?

Answer 18

The distribution of sample proportions (p-hats) computed from n will be approximately normally distributed.

Question 19

vv

Answer 19

p-hat = 320/500 = 0.64

Question 20

Given the following 99.7% confidence interval for the true proportion of FSU students who can pass the “mirror test”, what would be the best choice for the margin of error?

0.68 < p < 0.96

Answer 20

MoE = 0.14

Question 21

Given the following 99.7% confidence interval for the true proportion of FSU students who can pass the “mirror test”, what would be the best choice for the margin of error?

0.68 < p < 0.96

Answer 21

0.14

Question 22

In order to increase the precision of an interval estimate without

Answer 22

hhs