[Answered] MATH399N Week 5 Discussion: Interpreting Normal Distributions

Initial Post Instructions

Week 5 Graded Discussion:

Log onto website where you can observe your service bill for the last 12 months (electric bill, cell phone bill, water bill, etc.). If you do NOT feel comfortable sharing this data, you can make up values.

  1. In excel, list the values of your bill for the last 12 months on one column.
  2. Find the sample mean and sample standard deviation of your data.
  3. Pick three bills from the last 12 months and change the values into z-scores. What does the z-score tell you about that particular month?

Analysis

  1. Between what two values would be considered a normal bill? Remember, being within 2 Standard Deviations is considered normal.
  2. Are any of your bills in the last 12 months unusual? Very unusual?
  3. Are there times when you would accept an “unusual” bill? Explain.

 

 

Solution

Below is a table that depicts the electric bill for each month. (Obviously, I made up my values, or else I would be broke, lol).

Month Bill ($)
January 523.90
February 510.23
March 545.65
April 514.23
May 550.71
June 505.87
July 525.34
August 600
September 569.42
October 500.20
November 533.12
December 507.11

Using Microsoft Excel, the mean for this data was calculated to be μ=$532.15 with a standard deviation of σ=29.8. The three-monthly bills that were chosen for the analysis of z-scores are…………..please follow the link below to purchase the solution at $5