Question

VIII. Regarding the data offered in problem VII, we are interested in identifying which is the best statistical relationship between the variables considered.

Using all the information previously obtained by you I analyzed:

(1) the correlation coefficients, identifying which is the best and the weakest among all the possible regressions and equations.
(2)  the regression errors obtained, identifying which is the best and the weakest among all the possible regressions and equations.
(3) the required hypothesis tests

-(4) Present and identify which is the best equation to predict the monthly average purchase volume, explain why it is the best equation.

(5) With the best estimated equation present the confidence interval to predict the monthly average purchase volume, when the Area of
the store is 585, the family income is 50,000 and the parking number is 10.

Stores	Daily Sales	Store Area	Parking Space	Income (thousand of dollars)
1	$1840	532	6	44
2	1746	478	4	51
3	1812	530	7	45
4	1806	508	7	46
5	1792	514	5	44
6	1825	556	6	46
7	1811	541	4	49
8	1803	513	6	52
9	1830	532	5	46
10	1827	537	5	46
11	1764	499	3	48
12	1825	510	8	47
13	1763	490	4	48
14	1846	516	8	45
15	1815	482	7	43

Answer 1

I solved in excel- in Excel use data analysis tool to do regression anlysis and correlation coefficent

Answer(1) - correlation coefficient

taking realtion between daily sale and parking ,area and income is best regression equation beacuse R-sqaure is high for this model and standard error is also low

Best regression Equation is

daily sale=1480.74 + 0.73 * area +9.99 * parking--2.31 * Income

  

and weakest model is when daily sale and parking and income we consider as regression model.R-sqaure is low and standard error is also high

weakest regression equation is

daily sales=1914.69 +10.24 * parking -3.55*income

Answer (2)

regression error is best =13.42 and weakest model error =21.59

Answer(4) daily sale=1480.74 + 0.73 * area +9.99 * parking--2.31 * Income

beacuse in this case geeting less standard error and model is fit more accurately and we can predict the daily sales more accurately for future .

Answer(5)  when the Area of the store is 585, the family income is 50,000 and the parking number is 10.

daily sales= 1480.74 + 0.73 * area +9.99 * parking--2.31 * Income

=1480.74 + 0.73 * 585 +9.99 * 10--2.31 * 50=1892.19