# Assignment #1

#### Cynthia Boettcher

##### New member
How would I determine whether or not the data is "normal data"?

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#### Cynthia Boettcher

##### New member
If you have a set of data, how can you figure out if it's normal data?

#### Jomo

##### Elite Member
I guess that you should use one of the methods you have been taught. Which one do you think it is? What problems did you have trying to use that method? Can we see your work so that we can help you solve your problem?

#### Otis

##### Senior Member
How would I determine whether or not the data is "normal data"?
Hi Cynthia. Were you able to follow the given example? If not, which parts do you need help understanding?

For example, can you calculate the data set's median and mean? Did you sketch a histogram?

#### lolastorm

##### New member
I won't give you results or formulas (maybe a small one) .In this problem you have to:

• calculate mean and median
• calculate standard deviation
• sketch a histogram to check for bell rule
• check for empirical rule. The empirical rule is I believe checked by first calculating the margin of error in ranges of data (68%,95%, and 99.7%). Senior members feel free to fix the theoretical jargon if I am wrong........................................[edited]
68% range is calculated by using mean$$\displaystyle \pm$$deviation.
For 95% range the deviation factor is 2 which translates to [Mean$$\displaystyle \pm$$2*deviation]
For 99.7% range you can already guess.

Later we count the numbers that fall into these three ranges. I'm not sure how to be mathematically certain but if almost all data falls into at least 2 ranges the data should be normal in my opinion. I would be worried if more than 5 numbers don't fall in the ranges though.

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#### Dr.Peterson

##### Elite Member
I won't give you results or formulas (maybe a small one) .In this problem you have to:
• calculate mean and median
• calculate standard deviation
• sketch a histogram to check for bell rule
• check for imperial rule. The imperial rule is I believe checked by first calculating the margin of error in ranges of data (68%,95%, and 99.7%). Senior members feel free to fix the theoretical jargon if I am wrong. See below.
68% range is calculated by using mean$$\displaystyle \pm$$deviation.

For 95% range the deviation factor is 2 which translates to [Mean$$\displaystyle \pm$$2*deviation]

For 99.7% range you can already guess.

Later we count the numbers that fall into these three ranges. I'm not sure how to be mathematically certain but if almost all data falls into at least 2 ranges the data should be normal in my opinion. I would be worried if more than 5 numbers don't fall in the ranges though.
The word is "empirical", not "imperial"; read the paper carefully!

As for mathematical certainty, that's impossible. There are much more advanced techniques, discussed in the article in post #3. At this level, you are just making a largely subjective determination whether the data seem approximately normal. That word is repeated many times in the assignment.

#### lolastorm

##### New member
The word is "empirical", not "imperial"; read the paper carefully!

As for mathematical certainty, that's impossible. There are much more advanced techniques, discussed in the article in post #3. At this level, you are just making a largely subjective determination whether the data seem approximately normal. That word is repeated many times in the assignment.
Ah sorry for mixing up "empirical" and "imperial" .I will be more careful next time! I wish I could edit it out.

As for mathematical certainty thanks for explaining it. I will check it out.