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Calculating standard deviation, EXCEL

Using an excel spreadsheet and the stdav function calculate the following data and answer the following questions nunderneath

The data I choose to observe was how long I spent doing dishes over a 10-day period.

Friday, day 1 - 12 minutes.
Saturday, day 2 - 19 minutes.
Sunday, day 3 - 22 minutes.
Monday, day 4 - 0.
Tuesday, day 5 - 17 minutes.
Wednesday, day 6 - 15 minutes.
Thursday, day 7 - 12 minutes.
Friday, day 8 - 11 minutes.
Saturday, day 9 - 11 minutes.
Sunday, day 10 - 14 minutes.

Calculate the Standard Deviation of your data.

Is this a normal distribution?

What are the implications?

Solution Preview

The standard deviation would be 5.926400444
The average is 13.3 min
To test for normal distribution, we can look at the skew of the data. This is -0.988717886, which tells us that the data is skewed to the left, so on most days you did less then 13.3 minutes of dish washing. However, one day you did not do any dishes, which will definitely impact the data, which is seen as an outlier.

What if we took at day 4 ...

Solution Summary

This posting uses excel to calculate standard deviations. The excel worksheet is attached to the posting. It also looks at characteristics of the data such as is the distribution is normal (or is it skewed)? It also discusses the implications of having non-normal data.