44 lines
1.6 KiB
C#
44 lines
1.6 KiB
C#
|
using System;
|
||
|
|
using System.Collections.Generic;
|
||
|
|
using System.Linq;
|
||
|
|
|
||
|
|
namespace Unity.PerformanceTesting.Statistics
|
||
|
|
{
|
||
|
|
static class ConfidenceLevelExtensions
|
||
|
|
{
|
||
|
|
private static readonly Dictionary<ConfidenceLevel, (int value, int digits)> k_ConfidenceLevelDetails = CreateConfidenceLevelMapping();
|
||
|
|
|
||
|
|
/// <summary>
|
||
|
|
/// Calculates Z value (z-star) for confidence interval
|
||
|
|
/// </summary>
|
||
|
|
/// <param name="level">ConfidenceLevel for a confidence interval</param>
|
||
|
|
/// <param name="n">Sample size (n >= 3)</param>
|
||
|
|
public static double GetZValue(this ConfidenceLevel level, int n)
|
||
|
|
{
|
||
|
|
if (n <= 1)
|
||
|
|
throw new ArgumentOutOfRangeException(nameof(n), "n should be >= 2");
|
||
|
|
return StudentDistributionHelper.InverseTwoTailedStudent(1 - level.ToPercent(), n - 1);
|
||
|
|
}
|
||
|
|
|
||
|
|
static double ToPercent(this ConfidenceLevel level)
|
||
|
|
{
|
||
|
|
(int value, int digits) = k_ConfidenceLevelDetails[level];
|
||
|
|
|
||
|
|
return value / Math.Pow(10, digits);
|
||
|
|
}
|
||
|
|
|
||
|
|
static Dictionary<ConfidenceLevel, (int value, int length)> CreateConfidenceLevelMapping()
|
||
|
|
{
|
||
|
|
return Enum.GetValues(typeof(ConfidenceLevel))
|
||
|
|
.Cast<ConfidenceLevel>()
|
||
|
|
.ToDictionary(
|
||
|
|
confidenceLevel => confidenceLevel,
|
||
|
|
confidenceLevel =>
|
||
|
|
{
|
||
|
|
var textRepresentation = confidenceLevel.ToString().Substring(1);
|
||
|
|
return (int.Parse(textRepresentation), textRepresentation.Length);
|
||
|
|
});
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|