Assume that females have pulse rates that are normally distributed with a mean of

=74.0

beats per minute and a standard deviation of

=12.5

beats per minute. Complete parts (a) through (c) below.

Question content area bottom

Part 1

a. If 1 adult female is randomly selected, find the probability that her pulse rate is less than

77

beats per minute.

The probability is

enter your response here.

(Round to four decimal places as needed.)

Part 2

b. If

4

adult females are randomly selected, find the probability that they have pulse rates with a mean less than

77

beats per minute.

The probability is

enter your response here.

(Round to four decimal places as needed.)

Part 3

c. Why can the normal distribution be used in part (b), even though the sample size does not exceed 30?

A.

Since the original population has a normal distribution, the distribution of sample means is a normal distribution for any sample size.

B.

Since the distribution is of individuals, not sample means, the distribution is a normal distribution for any sample size.

C.

Since the distribution is of sample means, not individuals, the distribution is a normal distribution for any sample size.

D.

Since the mean pulse rate exceeds 30, the distribution of sample means is a normal distribution for any sample size.

A random sample of

857

births in a state included

426

boys. Construct a

95%

confidence interval estimate of the proportion of boys in all births. It is believed that among all births, the proportion of boys is

0.513.

Do these sample results provide strong evidence against that belief?

Question content area bottom

Part 1

Construct a

95%

confidence interval estimate of the proportion of boys in all births.

(Round to three decimal places as needed.)

Part 2

Do these sample results provide strong evidence against that belief?

A.

There is strong evidence against

0.513

as the value of the proportion of boys in all births because

0.513

is contained within the

95%

confidence interval.

B.

There is strong evidence against

0.513

as the value of the proportion of boys in all births because

0.513

is not contained within the

95%

confidence interval.

C.

There is not strong evidence against

0.513

as the value of the proportion of boys in all births because

0.513

is contained within the

95%

confidence interval.

D.

There is not strong evidence against

0.513

as the value of the proportion of boys in all births because

0.513

is not contained within the

95%

confidence interval.

A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before treatment,

17

subjects had a mean wake time of

101.0

min. After treatment, the

17

subjects had a mean wake time of

97.6

min and a standard deviation of

24.5

min. Assume that the

17

sample values appear to be from a normally distributed population and construct a

90%

confidence interval estimate of the mean wake time for a population with drug treatments. What does the result suggest about the mean wake time of

101.0

min before the treatment? Does the drug appear to be effective?

Question content area bottom

Part 1

Construct the

90%

confidence interval estimate of the mean wake time for a population with the treatment.

enter your response here

min<

min

(Round to one decimal place as needed.)

Part 2

What does the result suggest about the mean wake time of

101.0

min before the treatment? Does the drug appear to be effective?