Ice cream sales at a local ice cream shop on a particular day are linearly related to the temperature as depicted in the following chart. The regression line is y = 4.193x - 163.41, where x is the day's (average) temperature and y is the total sales for the day. The value of r 2 is 0.7.

a. Use the regression line to estimate the daily sales when the temperature is 80 degrees.

b. Use the regression line to predict the daily sales when the temperature is 95 degrees.

c. What is the slope of the regression line and what are the units of measurement? In a sentence,

interpret what the slope is telling us, in the context of this real-world application.

d. What is the value of the correlation coefficient, r? Also, interpret its value: looking at the graph

and size of r: Is the linear relationship positive or negative and do you judge the strength of the

linear relationship to be very strong, moderately strong, somewhat weak, or very weak?