Assignment
This assignment requires the use of spreadsheet software to analyze cost data using regression analysis and scatter plot graphs. The data to be analyzed are shown in the accompanying spreadsheet. Your assignment is as follows:
I. Produce ten scatter plot graphs with the number of pizzas sold as the predictor variable. The scatter plot graphs for the nine expenses and total costs should show the actual data points.
II. Add a trend line, regression output, and R-square statistic for each scatter plot graph. [The number of pizzas is the independent variable (X) and the cost data is the dependent variable (Y).]
III. Prepare a summary table by using selected data from the regression output: the constant (a), the X coefficient (b), and the R-square statistic for each cost item. A check row should be used to total the "a" and "b" coefficients for the nine expenses. These totals should be equal to the regression output for the total expense line.
IV. Time series scatter plot graphs for the cost items. (Several cost items could be combined on one graph).
V. The time series plots may reveal information about cost behavior patterns that are more useful for predictive purposes than the regression data based on volume. For each cost equations, explain whether the regression equation or the time series graph is a better predictor of costs.