19. A phone company has a monthly cellular data plan where a customer pays a flat monthly fee of $10 and then a certain amount of money per megabyte (MB) of data used on the phone. If a customer uses 20 MB, the monthly cost will be $11.20. If the customer uses 130 MB, the monthly cost will be $17.80.
a. Multiple choice: The linear regression model most closely fitting this data (where c represents monthly plan cost in dollars and d represents MB of data used) is:
A. ???? = −0.06???? +10 C. ???? = −16.67???? +10
B. ???? = 0.06???? +10 D. ???? = 16.67???? +10
b. Use the model to predict monthly plan cost if 200 MB are used (round answer to nearest cent if necessary) Show work!
c. Fill in the blanks to interpret the slope of the equation: The rate of change of US high school dropout rate with respect to time is
____________________ per ______________. (Include units of measurement.)