Question

A research council wants to estimate the mean length of time (in minutes) that the average U.S. adult spends watching television using digital video recorders (DVR’s) each day. To determine the estimate, the research council takes random samples of 35 U.S. adults and obtains the following times in minutes.

24 |
27 |
26 |
29 |
33 |

21 |
18 |
24 |
23 |
34 |

17 |
15 |
19 |
23 |
25 |

29 |
36 |
19 |
18 |
22 |

16 |
45 |
32 |
12 |
24 |

35 |
14 |
40 |
30 |
19 |

14 |
28 |
32 |
15 |
39 |

From past studies, the research council has found that the standard deviation time is 4.3 minutes and that the population of times is normally distributed.

Construct a 90% confidence interval for the population mean.

Construct a 99% confidence interval for the population mean.

Interpret the results and compare the widths of the confidence intervals.

Test the claim that the mean time spent watching DVR’s is not 20 minutes each day using a significance level of 0.05. Remember that the alternative hypothesis reflect what the researcher's claim. Be sure to state the null and alternative hypotheses.

Answer #1

A research council wants to estimate the mean length of time (in
minutes) that the average U.S. adult spends watching television
using digital video recorders (DVR’s) each day. To determine the
estimate, the research council takes random samples of 35 U.S.
adults and obtains the following times in minutes.
24
27
26
29
33
21
18
24
23
34
17
15
19
23
25
29
36
19
18
22
16
45
32
12
24
35
14
40
30
19
14...

A publisher wants to estimate the mean length of time? (in
minutes) all adults spend reading newspapers. To determine this?
estimate, the publisher takes a random sample of 15 people and
obtains the results below. From past? studies, the publisher
assumes standard deviation is 1.7 minutes and that the population
of times is normally distributed.
9
10
6
8
11
7
10
8
7
12
12
11
9
9
9
Construct the? 90% and? 99% confidence intervals for the
population...

A publisher wants to estimate the mean length of time (in
minutes) all adults spend reading newspapers. To determine this
estimate, the publisher takes a random sample of 15 people and
obtains the results below. From past studies, the publisher
assumes sigma is 2.7 minutes and that the population of times is
normally distributed. 12 12 6 9 11 12 9 9 11 10 6 6 12 6 6
Construct the 90% and 99% confidence intervals for the population
mean....

A publisher wants to estimate the mean length of time (in
minutes) all adults spend reading newspapers. To determine this
estimate, the publisher takes a random sample of 15 people and
obtains the results below. From past studies, the publisher
assumes sigma σ is 2.1 minutes and that the population of times is
normally distributed. 6 9 6 11 6 7 10 12 8 6 8 9 10 10 9
Construct the 90% and 99% confidence intervals for the
population...

A publisher wants to estimate the mean length of time (in
minutes) all adults spend reading newspapers. To determine this
estimate, the publisher takes a random sample of 15 people and
obtains the results below. From past studies, the publisher
assumes sigma is 2.1 minutes and that the population of times is
normally distributed.
6 10 12 6 6 10 7 7 8 8 11 11 9 10 7
Construct the 90% and 99% confidence intervals for the
population mean....

A publisher wants to estimate the mean length of time (in
minutes) all adults spend reading newspapers. To determine this
estimate, the publisher takes a random sample of 15 people and
obtains the results below. From past studies, the publisher
assumes sigma is 1.9 minutes and that the population of times is
normally distributed. 10 10 8 10 10 6 10 11 7 9 7 7 8 12 11
Construct the 90% and 99% confidence intervals for the population
mean....

The Buffalo, New York, Chamber of Commerce wants to estimate the
mean time workers who are employed in the downtown area spend
getting to work. A sample of 15 workers reveals the following
number of minutes spent traveling.
14
24
24
19
24
7
31
20
26
23
23
28
16
15
21
Develop a 98% confidence interval for the population mean
Confidence interval is between _________ and _______

A publisher wants to estimate the mean length of time (in
minutes) all adults spend reading newspapers. To determine this
estimate, the publisher takes a random sample of 15 people and
obtains the results below. From past studies, the publisher
assumes
sigmaσ
is
2.22.2
minutes and that the population of times is normally
distributed.
99
88
99
1111
66
99
99
77
1212
77
1212
66
99
1212
99
Construct the 90% and 99% confidence intervals for the
population mean....

publisher wants to estimate the mean length of time (in
minutes) all adults spend reading newspapers. To determine this
estimate, the publisher takes a random sample of 15 people and
obtains the results below. From past studies, the publisher
assumes sigmaσ is1.9 minutes and that the population of times is
normally distributed.
11
7
8
12
7
11
6
6
9
9
7
8
10
8
10
Construct the 90% and 99% confidence intervals for the
population mean. Which interval...

____________________________________________
The results of a sample of 372 subscribers to Wired
magazine shows the time spent using the Internet during the week.
Previous surveys have revealed that the population standard
deviation is 10.95 hours. The sample data can be found in the Excel
test data file.
What is the probability that another sample of 372 subscribers
spends less than 19.00 hours per week using the Internet?
____________________________________________
Develop a 95% confidence interval for the population mean
____________________________________________
If the editors...

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