Data from a sample of 10 pharmacies are used to examine therelationship between prescription sales volume and the percentageof prescription ingredients purchased directly from the supplier.The sample data is given below (Use formula to answer eachquestion).
percent ingredient 10 18 25 40 50 63 42 30 5 55
sales volume in $1000 25 55 50 75 110 138 90 60 10 100
a. Draw scatter plot between percent ingredient (x-variable) andthe sale volume (y variable). What can you say about theassociation between percent ingredient and the sale volume?
b. Calculate the mean and standard deviation for both predictor(% ingredient) and the response (sale volume) and samplecorrelation coefficient . ?
c. Use the information from part (a) above to determine theregression parameters (slope and intercept) using formula.
d. Interpret the slope in the context.ˆï¢
e. Write the equation of the regression line to predict salevolume from % ingredient
.f. Briefly describe goodness of fit of the fitted model thatyou have in part (d) above.g. Use the model to predict the salevolume when percent ingredient is 35%. Interpret the predictedvalue.
