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 SeattleWA 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
|
40
|
244
|
|
PA
|
14
|
47
|
|
NY
|
48
|
391
|
|
MA
|
18
|
159
|
a) Construct a scatter diagram of the data.
b) Find the equation for the line of best fit using x= miles and y=intersections.
c) Using the equation found in part (b), estimate the average number of intersections per mile along I-90.
d) Find a 95% confidence interval for β1.
e) Explain the meaning of the interval found in part d.