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How to collect data and compute mean and variance

From the 3 examples of random variables in life, discuss how would you go about collecting data to determine the mean and variance of each:

1. The number of times you tell your 3 kids to put down the toilet sit in a two week period, so the dogs stop drinking out of it especially with the poisonous toilet bowl cleaner.

2. How many laundry loads performed weekly for a family of 3? Consider workout clothes, church clothes, school and work clothes and most of all teenagers who put clean clothes back into the laundry basket without wearing them.

3. How many times will a Boxer 10 years old throw up his 2 meals per day of food in a week (this is a normal for a boxer)? Our family dog does this at each meal drives me crazy!

Solution Preview

The key to gathering data is to have a reliable way to capture the event. That usually means collecting the data in real time (not relying on memory)...

1. The number of times you tell your 3 kids to put down the toilet sit in a two week period, so the dogs stop drinking out of it especially with the poisonous toilet bowl cleaner.

So, I would likely have sheet on the wall taped up with a pencil to record each time I see the toilet seat up because it is at that moment I will yell out "someone forgot to put the seat down." I know it isn't my wife since she does not put the seat up!

Then, at the end of the month or the collection period, I would add up the number ...

Solution Summary

Several ideas are shared and a process for computing mean and variance are illustrated in excel.

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