statistical concepts

introduction to statistics  [cdf: version 1; version2; version 3]

mean

standard deviation (SD)

standard error of the mean  (SEM)

regression analysis  [for 2 parameter linear equation:  pptxpdf.]

p-value [alternative:  pdfpptx]

types of statistical test

Q-test

Table 1. Q-test values for 90% confidence.

N (sample size)

Q c

3

4

5

6

7

8

9

10

0.94

0.76

0.64

0.56

0.51

0.47

0.44

0.41

 

For example, is the value of 25 an outlier in the following data set ?

10, 11, 13, 14, 25.

In this example,

Q   =  | 25 - 14 |  ÷  (25 - 10)  =  0.73   >  Q c =  0.64

thus, the value of 25 is an outlier and may be deleted in subsequent data analysis

to compare 2 groups of data  [pdf,  pptx]

group 1
group 2
difference
X1
Y1
X1 - Y1
X2
Y2
X2 - Y2
etc.    
     
mean of group 1
mean of group 2
mean difference

use the following statistical test  [mathematica file that does these tests; requires mathematica]

2-sample t-test (or independent sample t-test or unpaired sample t-test)

1-sample t-test (or correlated sample t-test or paired sample t-test)

to compare 3 or more groups of data that differ by a single factor, use  [pptxpdf]

to compare groups of data that differ by two factors, use (optional)

 

additional resources: