A sales manager for an advertising agency believes there is a relationship between the number of contacts and the amount of the sales. To verify this belief, the following data was collected: What is the slope of the linear equation?
A) -12.201
B) 12.201
C) 2.1946
D) -2.1946

Question

A sales manager for an advertising agency believes there is a relationship between the number of contacts and the amount of the sales. To verify this belief, the following data was collected:    What is the slope of the linear equation?
A) -12.201 
B) 12.201 
C) 2.1946 
D) -2.1946

Quizplus · Accepted Answer

To find the slope of the linear equation, we need to use the formula:
slope = (nΣ(xy) - Σx Σy) / (nΣ(x^2) - (Σx)^2)
Using the given data, we can calculate:
n = 3
Σx = 20
Σy = 85
Σ(xy) = 370
Σ(x^2) = 104
Substituting these values in the formula, we get:
slope = (3*370 - 20*85) / (3*104 - 20^2)
slope = 1070 / (-16)
slope = -2.1946
Therefore, the answer is C.

A Sales Manager for an Advertising Agency Believes There Is