Cart
1. Select category 2. Choose calculator 3. Enter data 4. View results

Compare observed and expected frequencies

This calculator compares observed and expected frequencies with the chi-square test. Read an example with explanation.

Note that the chi-square test is more commonly used in a very different situation -- to analyze a contingency table. This is appropriate when you wish to compare two or more groups, and the outcome variable is categorical. For example, compare number of patients with postoperative infections after two kinds of operations. If you need to analyze a contingency table, do not use this table. If you have two groups (rows) and two outcomes, use this calculator. If your table is larger, try the free demos of GraphPad InStat (basic statistics only) and GraphPad Prism (statistics, nonlinear regression and scientific graphics).

Enter the names of the categories into the first column (optional). Enter the actual number of objects or individuals or events observed in the second column. Then enter the expected number, fraction or percent expected in the third column.

1. Choose data entry format

Enter up to 20 categories (rows).
Enter or paste up to 2000 categories (rows).
   Caution: Changing format will erase your data.

2. How will you enter the expected values?

Actual number expected
Percent expected
Fraction expected
Even if you enter the expected values as fractions or percentages, you must enter the the actual number of objects or individuals or events into the Observed column.

3. Enter data

        Category Observed # Expected
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:

4. View the results