Question

1. What percentage of data would you predict would be between 25 and 50 and what percentage would you predict would be more than 50 miles? Use the Week 4 spreadsheet again to find the percentage of the data set we expect to have values between 25 and 50 as well as for more than 50. Now determine the percentage of data points in the dataset that fall within each of these ranges, using same strategy as above for counting data points in the data set. How do each of these compare with your prediction and why is there a difference?

DRIVE:

44
20
88
6
71
42
76
63
61
63
84
28
55
33
88
80
86
83
5
85
25
25
54
54
81
73
29
76
78
77
42
65
71
94
6

Predicted percentage between 25 and 50: Actual percentage: Predicted percentage more than 50 miles: Actual percentage: Comparison: Why?

Answer 1

Answer:-

Given That:-

What percentage of data would you predict would be between 25 and 50 and what percentage would you predict would be more than 50 miles? Use the Week 4 spreadsheet again to find the percentage of the data set we expect to have values between 25 and 50 as well as for more than 50. Now determine the percentage of data points in the dataset that fall within each of these ranges, using same strategy as above for counting data points in the data set. How do each of these compare with your prediction and why is there a difference.

Mean of the data set

= 1948/36

= 54.11

Standard deviation

z score for X = 25

z score = (25 - 54.11)/28.29

= -1.03

z score =-1.03

z score for 50

z score = (50 - 54.11)/28.29

= -0.15

z score = -0.15

According to emperical rule

percentage area between -1.03 and -0.15 is 28.89% (from z - table)

That is predicted percentage of data between 25 to 50 is 28.89%

Actual percentage 22.22%

Note: Observations within 25 to 50 is 8, percentage = 8/36 = 0.2222 = 22.22%

Percentage area above -0.15 is 44.04% (from z table)

That is predicted percentage of data more than 50 is 44.04%

Actual percentage 61.11%

Note: Observations above 50 is 22, percentage = 22/36 = 0.6111 = 61.11%

Comparison: Between 25 to 50, actual percentage is less than predicted percentage.

For above 50, actual percentage is more than predicted percentage.

Why

The data is not symmetric data.

Predicted percentage between 25 and 50: 28.89%

Actual percentage: 22.22 %

Predicted percentage more than 50 miles: 44.04%

Actual percentage: 61.11 %

Comparison:  Between 25 to 50, actual percentage is less than predicted percentage. For above 50, actual percentage is more than predicted percentage.

Why?  

The data is not symmetric data.

Plz like it.....,