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If we have the following histogram:

And, want to describe it based on one of the following options, which one do you think is correct? Why?

1. positively skewed
2. symmetric
3. none of the above
4. negatively skewed

My initial suggestion would be “3. none of the above”.

What do you think?

Thanks.

whuber

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asked Apr 8, 2012 at 23:12

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I think you should ask yourself, if it isn’t symmetric, then why not? Is it really likely that something that is not symmetric is not skewed in either the negative or positive direction?

What is the feature about this histogram that makes you think it isn’t symmetric? Then, how would you describe that feature?

answered Apr 8, 2012 at 23:51

Peter Ellis
Peter Ellis

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Check out the wikipedia article http://en.wikipedia.org/wiki/Skewness.

I see that the mean and standard deviation are provided, not clear what is the statistic below that. If you are able to infer the median from this histogram, you could also calculate the Karl Pearson coefficient of skewness. This is defined as 3(mean – median) /Standard Deviation

If this statistic is greater than zero, the distribution is positively skewed, if negative then distribution is negatively skewed (this test might not work for bi-modal distributions though)

answered May 28, 2012 at 10:38

NaN
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The answer here is “1. positively skewed”.

answered Apr 9, 2012 at 12:28

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