Chi-Square Statistic
HardStatisticsMathArray
Description
Given an array of observed counts and a parallel array of expected counts, return the chi-square statistic: the sum over categories of (observed - expected)^2 / expected. Round the result to 4 decimal places.
Examples
Input:
[10,20,30], [20,20,20]Output:
10Explanation:
The chi-square statistic adds the squared gap between observed and expected counts, each scaled by its expected value.
Input:
[18,22], [20,20]Output:
0.4Explanation:
The chi-square statistic adds the squared gap between observed and expected counts, each scaled by its expected value.
Input:
[30,10], [20,20]Output:
10Explanation:
The chi-square statistic adds the squared gap between observed and expected counts, each scaled by its expected value.
Constraints
- •
1 ≤ length ≤ 10⁴ - •
every expected count > 0