Welch t Statistic

Compute Welch's t-statistic for two independent samples that may have different sizes and different variances. Use the unbiased sample variance (divide by $n-1n-1$).

Implement solve(a, b).

Returns. Return the statistic as a Python float. Each sample needs at least two values so that its variance exists.

Examples

Example 1

Input:

solve([5.0, 6.0, 7.0, 8.0], [1.0, 2.0, 3.0, 5.0])

Output:

3.503245

Example 2

Input:

solve([1.0, 2.0, 3.0], [1.0, 2.0, 3.0])

Output:

0.0