Statistical Analysis



A traffic safety officer conducted an experiment to determine whether there is a correlation between people's ages and driving speeds. Six individuals were randomly sampled and the following data were collected. Compute a Pearson r and then construct a least squares regression equation using age to predict driving speed.

Age(X)

20

25

45

46

60

65

Speed (mph)(Y)

60

47

55

38

45

35

Steps to Calculate Pearson r through SPSS

Go to analyze

Then Go to Bi-variate

Then select Correlation

Input the Variables and then click Ok

According to the study made by (Lehman Ann, 2005) the formula is:

Formula of Pearson r = ?XY - (?X)(?Y)

v (?X2-(?X)2 (?Y2- (?Y)2

nn

What is Pearson r -.698?

What is the least squares regression equation for using age to predict driving speed?

What percent of the variance in driving speed can we account for by knowledge of age? .360

Steps to Calculate Slope of regression line (

Go to analyze

Then Go to Regression

Then select Linear

Input the Variables as dependent(Speed) and Independent (Age)

Formula to calculate Slope of regression line (

= n (?XY) - (?X)(?Y)

n (?X2) -(?X)2



What is the slope of the regression line? -.371

5 . What number reflects the error in prediction? 7.68645

Formula to calculate Error of Prediction

Sy= v (?(y-yp) 2

n

Problem 2

A researcher collects data on the relationship between the amount of daily exercise an individual gets and the percent body fat of the individual. The following scores are recorded.

Individual

1

2

3

4

5

Exercise (min)

10

18

26

33

44

% Fat

30

25

18

17

14

Steps to Calculate Pearson r through SPSS

Go to analyze

Then Go to Bi-variate

Then select Correlation

Input the Variables and then click Ok

Formula of Pearson r = ?XY - (?X)(?Y)

v (?X2-(?X)2 (?Y2- (?Y)2

nn

What is Pearson r? -.959

What is the least squares regression equation for using exercise to predict % body fat?

What percent of the variance in percent body fat can we account for by exercise time in minutes? .892

What is the slope of the regression line? -.476

Steps to Calculate Slope of regression line (

Go to ...