Project #62320 - statistics

There are two projects due.. one is Monday and one is due Tuesday.   I will send in an attachment along with the dataset.

THIS SECTION IS DUE MONDAY MARCH 16

Data Worksheet  (see attached dataset)

1.  Means

2-day Mean                             _____________          2-day Standard Deviation                  ____________

4-day Mean                             _____________          4-day Standard Deviation                  ____________

14-day Mean                           _____________          14-day Standard Deviation                ____________

Control Group Mean               _____________          Control Group Standard Deviation    ____________

2.  Paired Differences

 2day-4day 2day-14day 4day-14day 52 114 62 2 21 19 -4 -32 -28 26 32 6 80 145 65 -4 16 20 14 18 4 38 4 -34 -12 -22 -10 -46 -12 34 -4 18 22 30 30 0 -38 -22 16 60 118 58 54 30 -24 -12 40 52 14 -30 -44 24 59 35 56 88 32 96 100 4 8 66 58 108 96 -12 62 134 72 30 80 50 10 83 73 40 32 -8 -26 -36 -10 -6 32 38 25 70 45 65 80 15

2-4 Day Mean                                     ________

2-4 Day Standard Deviation               ________

2-14 Day Mean                                   ________

2-14 Day Standard Deviation             ________

4-14 Day Mean                                   ________

4-14 Day Standard Deviation             ________

3.  Correlations

2-4 Day Correlation    ____________________

2-14 Day Correlation  ____________________

4-14 Day Correlation  ____________________

4.  Regression Equations

2-4 Day Regression    ____________________

2-14 Day Regression  ____________________

4-14 Day Regression   ____________________

Construct confidence intervals.   Use worksheet and dataset

a. One Mean on the 2 day
b. One Mean on the 4 day
c. One Mean on the 14 day
d. One Mean on the control group

a. Paired Difference between the 2 day and 4 day
b. Paired Difference between the 4 day and the 14 day
c. Paired Difference between the 2 day and the 14 day

a. Difference of Means between the 2 day and the control group
b. Difference of Means between the 4 day and the control group
c. Difference of Means between the 14 day and the control group

a. Proportion of the 2 day values greater than the control group mean
b. Proportion of the 4 day values greater than the control group mean
c. Proportion of the 14 day values greater than the control group mean

Find the control group mean on the worksheet. Now look at the 2-day column and compare the first number in the 2-day column with the control group mean. If the first number is larger than the control group mean, make a tally mark on a piece of paper. If it is smaller than ignore it. Do the same for the second number in the 2-day column and then the third and so forth. When you are done comparing all of the numbers in the 2-day column, count the number of tally marks. Divide this by the sample size and you'll have the necessary proportion.)

a. Difference in proportions between the 2 and 4 day over the control group mean
b. Difference in proportions between the 4 and 14 day over the control group mean
c. Difference in proportions between the 2 and 14 day over the control group mean

Be sure to show all of your work.

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THIS SECTION IS DUE TUESDAY MARCH 17

TEXTBOOK IS MIND ON STATISTICS 3RD EDITION (UTTS & HECKARD)

HOMEWORK QUESTIONS

10. Taking into account the purpose of a conï¬dence interval, explain what is wrong with the following statement: “Based on the survey data, a 95% conï¬dence interval estimate of the sample proportion is .095 to .117.”

25. In an ABCNews.com nationwide poll done in 2001, the proportion of respondents who thought that it should be illegal to use a handheld cellular telephone while driving a car was .69 (69%). The poll’s sample size was 1027.

a. Find the value of the standard error of the sample proportion.

b. Find a 95% conï¬dence interval estimate of the population proportion that thinks it should be illegal to use a cellular telephone while driving.

c. Find a 90% conï¬dence interval estimate of the population proportion that thinks it should be illegal to use a cellular telephone while driving.

44. In a study done in Maryland, investigators surveyed individuals by telephone about how often they get tension headaches (Schwartz et al., 1998). One response variable that was measured was whether or not the respondent had experienced an episodic tension-type headache (ETTH) in the prior year. A headache pattern was called episodic” if the headaches occurred less often than 15 times a month; otherwise, the headaches were called chronic.” Of the 1600 women in the survey aged 18 to 29, 653 said that they had experienced episodic tension-type headaches in the last year. Of the 2122 women in the 30- to 39-year-old age group, the number having experienced episodic headaches was 995.

a.       Estimate the proportion in each group that experienced an episodic headache in the prior year, and compute the difference in these two proportions.

b.      Compute a 95% conï¬dence interval for the difference between the proportions for these age groups in  the population. Write a sentence that interprets this conï¬dence interval.

46. In a survey of college students, 70% (.70) of the 100 women surveyed said that they believe in love at ï¬rst sight, whereas only 40% (.40) of the 80 men surveyed said that they believe in love at ï¬rst sight.

a.       Find the value of the difference between the sample proportions for men and women.

b.      Find the standard error of the difference between the sample proportions.

c.       Find an approximate 95% conï¬dence interval for the difference between population proportions believing in love at ï¬rst sight for men versus women

Chapter 11:

20.Explain what happens to the value of t* in each of the following cases.

a. The conï¬dence level is increased from 90% to 95%.

b. The sample size is increased.

c. The degrees of freedom are increased.

d. The degrees of freedom are essentially inï¬nite.

e. The standard error of the mean is decreased because the standard deviation is decreased.

24A random sample of n = 9 men between 30 and 39years old is asked to do as many sit-ups as they can in one minute. The mean number is  =26.2 and the standard deviation is s = 6.

a.           Find the value of the standard error of the sample mean. Write a sentence that interprets this value. Refer to 11.1 for guidance.  (Section 11.1 says - Would it be appropriate to use the ages of death of First Ladies given in Chapter 2 (Table 2.5, p. 28) to ï¬nd a 95% conï¬dence interval for the mean? If your answer is yes, what is the parameter of interest? If your answer is no, explain why not).

b.          Find a 95% conï¬dence interval for the population mean.

c.          Write a sentence that interprets the conï¬dence interval in the context of this situation.

37.  A random sample of ï¬ve college women was asked for their own heights and their mothers’ heights. The researchers wanted to know whether college women are taller on average than their mothers. The results (in inches) were as follows:

Pair             1          2          3          4          5

Daughter     66        64        64        69        66

Mother        66        62        65        66        63

a.       Deï¬ne the parameter of interest in this situation.

b.      Find a 95% conï¬dence interval for the parameter you deï¬ned in part (a).

c. Using the interval in part (b), write a sentence or two about the relationship between women students’ heights and their mothers’ heights for the population. Your explanation should be written to be understood by someone with no training in statistics.

44.  Refer to Exercise 11.25 (see below) about the effect of zinc lozenges on the duration of cold symptoms. For n = 25 in the zinc lozenge group, the mean overall duration of symptoms was 4.5 days, and the standard deviation was 1.6 days. For n =23 in the placebo group, the mean overall duration of symptoms was 8.1 days and the standard deviation was 1.8 days.

a.       Calculate 1 - 2 =  difference in sample means and also compute the unpooled s.e.(1 - 2)  = standard error of the difference in means.

b.      Compute a 95% conï¬dence interval for the difference in mean days of overall symptoms for the placebo and zinc lozenge treatments, and write a sentence interpreting the interval. Use the unpooled standard error and use the smaller of n1 - 1 and n2 - 1 as a conservative estimate of degrees of freedom.

c.       Is the interval computed in part (b) evidence that the population means are different? Explain.

11.25 says:

Volunteers who had developed a cold within the previous 24 hours were randomized to take either zinc or placebo lozenges every 2 to 3 hours until their cold symptoms were gone (Prasad et al., 2000). Twenty-ï¬ve participants took zinc lozenges, and 23 participants took placebo lozenges. The mean overall duration of symptoms for the zinc lozenge group was 4.5 days, and the standard deviation of overall duration of symptoms was 1.6 days. For the placebo group, the mean overall duration of symptoms was 8.1 days, and the standard deviation was 1.8 days.

 Subject Mathematics Due By (Pacific Time) 03/16/2015 10:00 pm
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