Regression Analysis.

The manager of a fast-food restaurant wants to determine how sales in each week are related to the number of discount vouchers (#) printed in the local newspaper during the week. The number of vouchers and sales ($000s) from 10 randomly selected weeks is given below:

Number of vouchers	Sales
4	12.8
7	15.4
5	13.9
3	11.2
19	18.7
10	17.9
8	16.8
6	15.9
3	11.5
5	13.9

Questions and Answers are provided below: Task is to go through this steps and check whether there is any mistake or not and summarise this answers into a brief/short report. Thanks!

1. Interpret the value of intercept coefficient & the slope of the regression line

The expected sales value when the number of vouchers in 0 is 11.5676. While, each increase of 1 in number of vouchers is estimated to result in an increase in sales by 0.4618.

2. Determine the coefficient of determination and discuss what the coefficients tell you about the relationship between the two variables.

The coefficient of the determination is 0.7267 and this indicates a very strong correlation between number of vouchers and sales. This also indicates that the percentage of variation in sales that can be explained by the number of vouchers is 72.67%.

3. Use the regression equation toPredict weekly sales in the fast-food restaurant if 10 vouchers are printed in the local newspaper.

predicted weekly sales = 16.1853

4. Plot the residuals against the predicted values.Plot the residuals against the predicted values ofy. Does the variance appear to be constant

Explanation:

Using this data we have to use the Excel's regression here are the steps

Step 1: Go to Data Menu

Step 2: Click Data Analysis

Step 3: Choose Regression, Click Ok

Step 4: For Input Y Range: Select the column for Sales values

Step 5: For Input X Range: Select the column for Numberof vouchers values

Step 6: Check the box for Labels

Step 7: Check the box for Residual Plots

Step 8: Click Ok

Here are the results: