Part 4. 4a. The correlation between a number of customers and sales in dollars i
ID: 3042494 • Letter: P
Question
Part 4.
4a. The correlation between a number of customers and sales in dollars in retail stores is r=0.6. To inflate the correlation, a conniving manager added $200,000 to the actual sales amount for each store. Would this trickery make the correlation larger?
A. No, there would be no change.
B. Yes, the correlation will become larger.
C. No, the correlation will become smaller.
4b. If two variables are linearly associated, the peak in the histogram of the explanatory variable will line up with the peak in the histogram of the other variable.
A. The statement is true.
B. The statement is false. The linear correlation implies that the histograms will be flat and without a peak.
C. The statement is false. It is only true if the linear relationship has a positive association, but is not in general true for linearly associated variables.
D.The statement is false. These are properties of the marginal distribution, not of the conditional distribution of y given x (or vice versa).
4c. The visual test for association is used to decide whether a plot has a real or imagined pattern.
A. The statement is true.
B. The statement is false. The visual test is used to identify any outliers or unexpected patterns.
C. The statement is false. The visual test is used to determine the correlation line for two variables.
D. The statement is false. The visual test is used to determine the strength and direction of the association.
Explanation / Answer
4a
A. No, there would be no change.
Because standard deviation will not change
4b)
The statement is false. It is only true if the linear relationship has a positive association, but is not in general true for linearly associated variables.
If negative correlation is there, then peak will coincide with trough.
4c)
B. The statement is false. The visual test is used to identify any outliers or unexpected patterns.