Focus Fanatics - View Single Post - 12 Focus Depreciation That Bad? Really? <DATA ANALYSIS INCLUDED>
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Old 02-01-2013, 02:35 PM   #39
gkirk
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Quote:
Originally Posted by Jdog913 View Post
Here are my thoughts. You presented nicely, comparing variables relative to others. (Good job there!) but you didn't check your data set for skewness. This is an extremely confusing topic for people who are not familiar with statistics.
<snip>

I recommend changing the sample size and taking the middle 20 numbers with respect to the median of the whole data set causing a more normally distributed curve. Then we can make conclusions of the data.

When this is done then we will most likely see,

* Z-Scores great than -2 and less than 2
* Means and Medians extremely close (Around 1 when divided)
* Bell Shape Curve


Care to explain how the data is valid?
Data is valid without any statistical analysis because it's data. The beautiful thing about presenting a lot of collected data is that the viewer can see all of it and make up their mind what biases, gaps, etc are missing.

While your desire for further analysis is admirable, I don't see how you can claim the data is invalid, any less than looking in the paper and seeing a car for sale is not valid.

As for the 'what does engineering have to do with it'. I think that comment was more directed at the fact that the rest of us know enough statistics to make up our minds about the validity of the original work.

Some data is better than no data, and the work done here is interesting and useful. Nobody is going to use it to build a nuclear weapon, so doing a lot of unreasonable stats on it is a waste of time.

I've had lots of arguments with people who 'understand' statistics better than me to know that most of the time, they have lost the basic understanding of what statistics is and how it works. Don't take this the wrong way, but you seem to fall into that category here.

What you are looking at is a bunch of data, not a statistical analysis.
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