Find the sample mean and sample standard deviation of your data.

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

Between what two values would be considered a normal bill? Remember, being within 2 Standard Deviations is considered normal.

Are any of your bills in the last 12 months unusual? Very unusual?

Are there times when you would accept an "unusual" bill? Explain

A fx C energy bill X B month January Februray March April May June July August September October November December mean standard dev D 51.93 14.12 14.1 14.49 z score 14.75 15.84 104.92 129.08 z score 115.17 72.71 22.54 36.97 z score 50.55 42.03 E -0.858 1.8684 -0.3231 F G A fx C energy bill X B month January Februray March April May June July August September October November December mean standard dev D 51.93 14.12 14.1 14.49 z score 14.75 15.84 104.92 129.08 z score 115.17 72.71 22.54 36.97 z score 50.55 42.03 E -0.858 1.8684 -0.3231 F G