Question

The data table below shows the number of computers sold at the Bronco Store in a week, based on online advertising.

Online Ads              Computers Sold

2                             25      

1                             10

4                             30

1                             10

Sx = 10

2                             25

	Sy = 100

a. Calculate the means for both Ads and Computers Sold.

b. Calculate the slope for the estimated regression equation.

The (x-x)(y-y) = 40, just need to calculate denominator.   

c. Calculate the y-intercept for the estimated regression equation.   

d. What is the estimated regression equation.

                                                    

Answer 1

	ΣX	ΣY	Σ(x-x̅)²	Σ(y-ȳ)²	Σ(x-x̅)(y-ȳ)
total sum	10	100	6	350.0	40.00
mean	2.00	20.00	SSxx	SSyy	SSxy

a)

sample size ,   n =   5      
here, x̅ = Σx / n=   2.00   ,     ȳ = Σy/n =   20.00

b)

SSxx =    Σ(x-x̅)² =    6.0000          
SSxy=   Σ(x-x̅)(y-ȳ) =   40.0          
                  
estimated slope , ß1 = SSxy/SSxx =   40.0   /   6.000   =   6.67

c)

intercept,   ß0 = y̅-ß1* x̄ =   6.67

d)

so, regression line is   Ŷ =   6.67   +   6.67   *x

Please revert back in case of any doubt.

Please upvote. Thanks in advance.