Refer to the FINAL EXAM TRAFFIC COUNTS Excel spreadsheet. Twenty stores in a sta
ID: 3369896 • Letter: R
Question
Refer to the FINAL EXAM TRAFFIC COUNTS Excel spreadsheet. Twenty stores in a statewide retail chain are surveyed. The table shows the total number of sales per store (expressed in thousands of dollars) and also the traffic count (number of cars that pass the store per day, expressed in thousands). Are sales related to traffic count?
a. State the null and alternate hypotheses.
b. Conduct the appropriate statistical test to test these hypotheses.
c. Did you find a significant relationship between sales and traffic count? If yes, carefully interpret the coefficient you obtained, in plain English.
d. Clearly state the interpretation of the Adjusted R Squared value you obtained.
TRAFFIC COUNTS DATA Average Daily Traffic Cunt in Thousands Store ID Annual Sales in Number Thousands of Dollar STORE SALES TRAFFIC 41 35 47 61 45 45 49 28 29 38 34 29 45 41 28 21 52 43 21 30 821 565 502 923 645 501 302 472 644 601 402 FRNE 10 12 13 14 15 16 17 18 19 20 297 457 772 801 544 583Explanation / Answer
Regression Analysis: traffic versus sales
a] null and alternate hypotheses
H0: beta1 = 0 vs H1: beta 1 is not equal to 0.
Model Summary
S R-sq R-sq(adj) R-sq(pred)
7.75776 49.52% 46.71% 38.96%
Coefficients
Term Coef SE Coef T-Value P-Value
Constant 13.56 6.09 2.23 0.039
sales 0.04155 0.00989 4.20 0.001
Regression Equation
traffic = 13.56 + 0.04155 sales
b] beta1 = 0.0416
Pvalue = 0.001 < alpha = 0.05
c] Reject H0 , There is significant relationship between sales and traffic count.
d] Adjusted R Squared = 0.4671
The adjusted R-squared is a modified version of R-squared that has been adjusted for the number of predictors in the model. Adjusted R squared is always less than R square.