The number of domestic and imported retail car sales (in hundreds of thousands)
ID: 3156992 • Letter: T
Question
The number of domestic and imported retail car sales (in hundreds of thousands) in the United States for a period of 9 years are given in the following table.
Year Domestic Car Sales Imported Car Sales
Year 1 69.8 17.2
Year 2 68.3 20.2
Year 3 63.2 20.9
Year 4 58.8 22.2
Year 5 55.3 20.9
Year 6 53.6 21.5
Year 7 54.8 22.0
Year 8 54.4 23.3
Year 9 52.5 23.8
Do the data exhibit a linear trend?
Yes, they are pretty reliable since the correlation coefficient is relatively close to 1.No, they are not reliable since the correlation coefficient is close to 0. No, they are not reliable since the slope is negative.Yes, they are pretty reliable since the correlation coefficient is relatively close to 1.Yes, they are reliable since the slope is positive.
Explanation / Answer
a)
YES, they exhibit a linear trend.
b)
Using technology, we get
slope = -0.244705541
intercept = 35.7628034
Thus, the regression line is
y^ = -0.244705541x + 35.7628034 [ANSWER]
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c)
Hence, x = 60.
Thus, if x = 60
Then
y^ = 21.08047094 [ANSWER]
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d)
Hence, x = 24.
Thus, if x = 24
Then
y^ = 29.88987042 [ANSWER]
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e)
Also, getting the correlation,
r = -0.830584172 [ANSWER]
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f)
r = -0.830584172 [which is close to -1]
Thus,
OPTION D: Yes, they are pretty reliable since the correlation coefficient is relatively close to 1 [ANSWER, D]