Mathematics - Statistics STA200 Homework 4:

STA200

Homework 4: Based on Chapter 4.

· To calculate the correlation factor (r), go to Excel, Formulas, Statistics, and select the CORREL function.

· To calculate the Regression Equation and Coefficient of Determination:

a. Select the x,y data

b. Insert a scatter chart from that data

c. Click the chart, go to Chart Design

d. Go to Quick Layout

e. Select Layout 9

f. Then you get the Regression Equation, and r square.

1) Exercise 23, page 159. Roadway congestion is a costly item, in both time wasted, and fuel wasted. Let X represent the average annual hours per person spent in traffic delays and let Y represent the average annual gallons of fuel wasted per person in traffic delays. a) Draw a scatter diagram for the data. b) Compute r (Coefficient of Correlation). c) Is there a correlation?

X (hr)	Y (gal)
28	48
5	3
20	24
35	55
20	34
23	38
18	28
5	9

2) Exercise 7, page 172. Let X represent the total number of jobs in each neighborhood, and let Y represent the number of entry-level jobs in the same neighborhood. A sample of six neighborhoods gave the following information (units in hundreds of jobs).

X	Y
16	2
33	3
50	6
28	5
50	9
25	3

a) Calculate the media of jobs. b) Calculate the media of entry-level jobs. c) Compute r (Coefficient of Correlation). d) Draw a scatter diagram for the data, showing the regression line. e) Calculate the Coefficient of Determination. f) Calculate the Regression Equation. g) Question: If a neighborhood with 40 jobs, how many are predicted to be entry-level jobs?