question 15

In a random sample of

24

people, the mean commute time to work was

31.2

minutes and the standard deviation was

7.2

minutes. Assume the population is normally distributed and use a t-distribution to construct a

95%

confidence interval for the population mean

.

What is the margin of error of

?

Interpret the results.

The confidence interval for the population mean

is ___,____

(Round to one decimal place as needed.)

The margin of error of

is ____

(Round to one decimal place as needed.)

Interpret the results.

A.

If a large sample of people are taken approximately

95%

of them will have commute times between the bounds of the confidence interval.

B.

It can be said that

95%

of people have a commute time between the bounds of the confidence interval.

C.

With

95%

confidence, it can be said that the population mean commute time is between the bounds of the confidence interval.

D. With

95%

confidence, it can be said that the commute time is between the bounds of the confidence interval.

question 16

The table lists the smoking habits of a group of college students.

Sex	Non-smoker	RegularSmoker	HeavySmoker	Total
Man	135	48	5	188
Woman	187	21	6	214
Total	322	69	11	402

If a student is chosen at random, find the probability of getting someone who is a man or a non-smoker. Round your answer to three decimal places.

question 17

Complete parts (a) and (b) below.

The number of dogs per household in a small town

Dogs	0	1	2	3	4	5
Probability	0.656	0.216	0.085	0.024	0.014	0.006

(a) Find the mean, variance, and standard deviation of the probability distribution.

Find the mean of the probability distribution.

=

(Round to one decimal place as needed.)

Find the variance of the probability distribution.

2=

(Round to one decimal place as needed.)

Find the standard deviation of the probability distribution.

=

(Round to one decimal place as needed.)

(b) Interpret the results in the context of the real-life situation.

A.

A household on average has

0.8

dog with a standard deviation of

0.9

dog.

B.

A household on average has

0.9

dog with a standard deviation of

0.5

dog.

C.

A household on average has

0.5

dog with a standard deviation of

0.9

dog.

D.

A household on average has

0.5

dog with a standard deviation of

11

dogs

question 19

For the following data (a) display the data in a scatter plot, (b) calculate the correlation coefficient r, and (c) make a conclusion about the type of correlation.The ages (in years) of

6

children and the number of words in their vocabulary

Age, x	1	2	3	4	5	6
Vocabulary size, y	400	400	1300	1400	1850	2300

a. draw scatter plot

(b) The correlation coefficient r is ___

(Round to three decimal places as needed.)(c) Which of the following best describes the type of correlation that exists between age and vocabulary size?

A.

Strong positive linear correlation

B.

Weak negative linear correlation

C.

Weak positive linear correlation

D.

Strong negative linear correlation

E.

No linear correlation