Download Homework 13

Homework 13
22s:39
Stramer
1. In order to investigate the feasibility of starting a Sunday edition for a large
metropolitan newspaper, information was obtained from a sample of 34 newspapers
concerning their daily and Sunday circulations (in thousands). The data are given below
and can be found in http://www.ats.ucla.edu/stat/examples/chp/P050.txt
Data Display
Row
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
Newspaper
Baltimore Sun
Boston Globe
Boston Herald
Charlotte Observer
Chicago Sun Times
Chicago Tribune
Cincinnati Enquirer
Denver Post
Des Moines Register
Hartford Courant
Houston Chronicle
Kansas City Star
Los Angeles Daily News
Los Angeles Times
Miami Herald
Minneapolis Star Tribune
New Orleans Times-Picayune
New York Daily News
New York Times
Newsday
Omaha World Herald
Orange County Register
Philadelphia Inquirer
Pittsburgh Press
Portland Oregonian
Providence Journal-Bulletin
Rochester Democrat & Chronicle
Rocky Mountain News
Sacramento Bee
San Francisco Chronicle
St. Louis Post-Dispatch
St. Paul Pioneer Press
Tampa Tribune
Washington Post
Daily
391.95
516.98
355.63
238.56
537.78
733.78
198.83
252.62
206.20
231.18
449.76
288.57
185.74
1164.39
444.58
412.87
272.28
781.80
1209.23
825.51
223.75
354.84
515.52
220.47
337.67
197.12
133.24
374.01
273.84
570.36
391.29
201.86
321.63
838.90
Sunday
488.51
798.30
235.08
299.45
559.09
1133.25
348.74
417.78
344.52
323.08
620.75
423.31
202.61
1531.53
553.48
685.98
324.24
983.24
1762.02
960.31
284.61
407.76
982.66
557.00
440.92
268.06
262.05
432.50
338.36
704.32
585.68
267.78
408.34
1165.57
(a) Construct a scatter plot of Sunday circulation versus daily circulation. Does the
plot suggest a linear relationship between Daily and Sunday Circulation?
(b) Fit a regression line predicting Sunday circulation from Daily circulation.
(c) Obtain a 95% confidence interval for the slope and intercept.
(d) Is there a significant relationship between Sunday circulation and Daily
circulation? Justify your answer by a statistical test. (Use F)
(e) Test the hypothesis H 0 :   0 vs Ha :   0 . Use   0.05 .
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2. A substance used in biological and medical research is shipped by
airfreight to users in cartons of 1000 ampoules. The data below,
involving 10 shipments, were collected on the number of times the
carton was transferred from one aircraft to another over the shipment
route (X=C1) and the number of ampoules found to be broken upon arrival
(Y). Assume that the simple linear regression model is appropriate.

Obtained the estimated regression line. Plot the estimated
regression line and the data.

Obtain a point estimate of the expected number of broken ampules
when X=1 transfer is made.

Verify that the fitted regression

Estimate

Conduct a t test to decide whether or not there is a linear
association between number of times a carton is transferred (X)
and number of broken ampoules (Y). What is the p-value? Use a
level of significance of .05.

A consultant has suggested, based on previous experience, that
the mean number of broken ampoules should not exceed 9 when no
transfers are made. Construct an appropriate test, using a level
of significance of 0.025. (will be discussed in class).
goes through
( X ,Y )
 with a 95 percent confidence interval.
Data Display
Row
1
2
3
4
5
6
7
8
9
10
C1
16
9
17
12
22
13
8
15
19
11
C2
1
0
2
0
3
1
0
1
2
0
2
3. The following is an output from Minitab for regressing the final scores for 21 students
on the midterm scores in a course in statistics.
Regression Analysis: Final Score versus Midterm Score
The regression equation is
Final Score = 20.964 + 0.7426 (Midterm)
Predictor
Constant
Midterm
Coef
20.964
0.7426
SE Coef
8.411
0.1050
T
2.49
7.08
P
0.023
0.000
S = 8.32572.
(a) What is the predictor variable? What is the response variable
(b) What is the regression equation?
(c) Suppose that Joe scores 80 on the first exam. Use the Minitab output to predict
his score on the final exam.
(d) In reality, Joe scores 85 on the final test. What is the residual for Joe?
(e) Find a 95% confidence interval for the slope.
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