QUESTION 1
To compare commuting eras in various locations, independent random examples were obtained from the six cities presented in the Longest Commute to Work graphic on page 255 in your textbook. The examples were from workers who commute to work during the 8:00 a.m. rush hour. One-way Travel to Work in Minutes
|
Atlanta
|
Boston
|
Dallas
|
Philadelphia
|
Seattle
|
St. Louis
|
|
29
|
18
|
42
|
29
|
30
|
15
|
|
21
|
37
|
25
|
20
|
23
|
24
|
|
20
|
27
|
26
|
33
|
31
|
42
|
|
15
|
25
|
32
|
37
|
39
|
23
|
|
37
|
32
|
20
|
42
|
14
|
33
|
|
26
|
34
|
26
|
18
|
48
|
35
|
a) Construct a graphic representation of the data using six sid-by-side dotplots.
ST.LOUIS ? ? ? ? ?
SEATTLE? ? ? ?
PHIL ? ? ? ? ?
DALLAS ? ? ? ? ?
BOSTON ? ? ? ? ? ?
ATLANTA ? ? ? ? ? ?
10 15 20 25 30 35 40 45 50
b) Visually approximation the mean commute time for each city and locate it with an X.
c) Does it seem that different cities have different effects on the average amount of time spent by workers who commute to work during the 8:00 a.m. rush hour? Explain.
d) Does it visually seem that different cities have different effects on the variation in the amount of time spent by workers who commute to work during the 8:00 a.m. rush hour? Explain.
Part 2
a) Compute the mean commute time for each city depicted.
b) Does there look to be a difference among the mean one-way commute times for these six cities?
c) Compute the standard deviation for each city's commute time.
d) Does there look to be a difference among the standard deviations between the one-way commute times for these six cities?
Part 3
a) Construct the 95% confidence intermission for the mean commute time for Atlanta and Boston.
b) x-bar: Sample mean = 28.6
c) s: Sample = 8.6
n: Number of samples = 36
df: degrees of freedom = 35
significant digits = 1
28.6 ± 2 * 8.6/SQRT=36 = 25.7, 31.5
d) Established on the confidence intervals found does it appear that the mean commute time is the same or different for these two cities (Atlanta and Boston). Elucidate
e) Yes, because Interstate 90 is the lengthiest of the east-west U.S. interstate highways with its 3,122 miles stretching from Boston, MA at I-93 on the eastern end to Seattle WA at the Kingdome on the western end. It travels across 13 northern states the number of miles and number of intersections in each of those states is listed below
f) Build the 95% confidence interval for the mean commute time for Dallas.
g) Based on the confidence intervals originate in (Atlanta and Boston) and Dallas does it appear that the mean commute time is the same or different for Boston and dalls? Explain.
h) Based on the confidence levels originate in (Atlanta and Boston) and (Dallas) does it appear that the mean commute time is the same or different for the set of three cities, Atlanta, Boston, and Dallas? Explain
i) How does your confidence intervals compare to the intervals given for Atlant, Boston, and Dallas in Longest Commute to Work on page 255?
Question 2
Interstate 90 is the longest of the east-west U.S. interstate highways with its 3,112 miles stretching from Boston, MA at I-93 on the eastern end to Seattle WA at the Kingdome on the western end. It travels across 13 northern states; the number of miles and number of intersections in each of those states is listed below.
|
State
|
No. of Inter
|
Miles
|
|
WA
|
57
|
298
|
|
ID
|
15
|
73
|
|
MT
|
83
|
558
|
|
WY
|
23
|
207
|
|
SD
|
61
|
412
|
|
MN
|
52
|
275
|
|
WI
|
40
|
188
|
|
IL
|
19
|
103
|
|
IN
|
21
|
157
|
|
OH
|
14
|
47
|
|
PA
|
14
|
47
|
|
NY
|
48
|
391
|
|
MA
|
18
|
159
|
a) Create a scatter diagram of the data
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? ?
b) Discover the equation for the line of best fit using x= miles and y=intersections
Y = 4.64698929 + 0.138364119(X)
c) Using the equation found in part (b) approximation the average number of intersections per mile along I-90 The "average" will take place at the point where the "residual equals zero". I think subsequently the residual equal zero, then the intersections average is 38 average.
d) Find a 95% confidence interval for β1.
Y = 4.64698929 + 0.138364119(X)
e) Describe the meaning of the interval found in part d
I consider since the value 0 is excluded from the Interval then there must be a positive relationship between x and y