Expected difference between two populations' median

tails:

Target: To check if the diffrence between the average (mean) of two or more groups (populations) is significant, using sample data
ANOVA is usually used when there are at least three groups, since for two groups you can use t tests.

Example1: A farmer use four differnt fertilizers in four fields. The farmer compare sample average of apples' weight from each field to decide if the difference between the fertilizers is significant.

Assumptions

Independent samples

Normal distribution of the analyzed population

Equal standard deviation, σ_{1}=σ_{2}=...=σ_{k}

Required Sample Data

Sample data from all compared groups

Parameters

k - Number of groups. n_{i} - Sample side of group i. n - Overall sample side, includes all the groups (Σn_{i}, i=1 to k). x_{i} - Average of group i. x - Overall average (Σx_{i,j} / n, i=1 to k, j=1 to n_{i}). S_{i} - Standard deviation of group i.

c - continuity correction, when U > μ: c = -0.5, when U < μ: c = 0.5

Test calculation

The tool uses the critical value tables when n ≤ 25 and a normal approximation for a larger sample size

Statistic Data

Enter sample data directly

Header:
You may change groups' name to the real names. Data:
When entering data, press Enter after each value.
Difference = Right - Left

It is okay to leave empty cells, empty cells or non numeric cells won't be counted

Enter sample data from excel

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 consecutive columns includes the header, and paste below.
. click to see example:

It is okay to leave empty cells, empty cells or non numeric cells won't be counted