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Lab 5

After plotting the normal probability plot, I can see that the graph is not normal. I cannot seem to get the graphs out of PAST, but will try to do so in class.  For the most part, graphs of the Normal Probably Plot are showing a log scale relationship, with C having the inverse of this.  Taking the log of shape length and plotting it the same way gives me an s shaped graph with the left side lower and the right side slightly raised.  So this is much closer to a normal distribution, but from what I am reading, the S shape means that there is more variability than a normal distribution.  

Below are the univariate statistics for shape length and shape area.  You can see in the length chart the minimum value of 30, a max of 3734, and a mean of 184, that the values are skewed toward the lower end.  The standard deviation of 80, tells me that the values are not that widely off, and that there are most likely outliers toward the upper limits.  The graphs shows that there is at least one value that is significantly larger than the rest, it does however line up along a curve with the other values, suggesting that a log scale might work on this data to better conform to a normal distribution.  

0 Shape_Leng
N 11737
Min 30.75888
Max 3734.881
Sum 2169967
Mean 184.8826
Std. error 0.7394023
Variance 6416.804
Stand. dev 80.10495
Median 169.0816
25 prcntil 138.6115
75 prcntil 211.7965
Skewness 9.702852
Kurtosis 500035.8
Geom. mean 173.7321

 

Shape_Leng

N

11737

Min

30.75888

Max

3734.881

Sum

2169967

Mean

184.8826

Std. error

0.7394023

Variance

6416.804

Stand. dev

80.10495

Median

169.0816

25 prcntil

138.6115

75 prcntil

211.7965

Skewness

9.702852

Kurtosis

500035.8

Geom. mean

173.7321

 

Shape_Area

N

11737

Min

67.93181

Max

682473.5

Sum

3.35E+07

Mean

2850.52

Std. error

63.74081

Variance

4.77E+07

Stand. dev

6905.516

Median

2095.673

25 prcntil

1406.141

75 prcntil

3276.017

Skewness

82.01563

Kurtosis

1.15E+07

Geom. mean

2186.083


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