Target: To check if the difference between the average (mean) of two groups (populations) is significant, using sample data
Example1: A man of average hight is expected to be 10cm taller than a woman of average hight (d=10)
Example2: The average weight of an apple grown in field 1 is expected to be equal in weight to the average apple grown in field 2 (d=0)
Normal distribution | |
σ_{1},σ_{2} - The standard deviations of both populations are known ( so either σ_{1}=σ_{2} or ϭ_{1}≠ϭ_{2 }) | |
Expected difference d between the populations's average is known |
x_{1}, x_{2} - Sample average of group1 and group2 | |
n_{1},n_{2} - Sample size of group1 and group2 |
If you enter raw data, the tool will run the Shapiro-Wilk normality test and calculate outliers, as part of the test calculation.
Header:
You may change groups' name to the real names.
Data
When entering data, press Enter after each value
You may copy data from Excel, Google sheets or any tool that separate data with Tab and Line Feed.
Copy the data, one block of 2 consecutive columns includes the header, and paste below.
x_{1}: | Sample average of group1 | |
n_{1}: | Sample size of group1 | |
σ_{1}: | Standard deviation of group1 | |
S_{1}: | Sample Standard deviation of group1, S_{1} is NOT mandatory, but will help to validate σ_{1} | |
skewness: | ||
Normality pval1: | Shapiro Wilk test | |
Outliers | count: ,based on the Tukey's fences method, k=1.5 | |
The difference between the expected SD and the sample SD
x_{2}: | Sample average of group2 | |
n_{2}: | Sample size of group2 | |
σ_{2}: | Standard deviation of group2 | |
S_{2}: | Sample Standard deviation of group2, S_{2} is NOT mandatory, but will help to validate σ_{2} | |
skewness: | ||
Normality pval2: | Shapiro Wilk test | |
Outliers | count: ,based on the Tukey's fences method, k=1.5 | |