/// <summary>
/// Tests whether the means of two samples are different.
/// </summary>
/// <param name="sample1">The first sample.</param>
/// <param name="sample2">The second sample.</param>
/// <param name="hypothesizedDifference">The hypothesized sample difference.</param>
/// <param name="assumeEqualVariances">True to assume equal variances, false otherwise. Default is true.</param>
/// <param name="alternate">The alternative hypothesis (research hypothesis) to test.</param>
public TwoSampleZTest(DescriptiveResult sample1, DescriptiveResult sample2,
double hypothesizedDifference = 0, TwoSampleHypothesis alternate = TwoSampleHypothesis.ValuesAreDifferent)
{
// References: http://en.wikipedia.org/wiki/Student's_t-test#Worked_examples
Compute(sample1.Mean, sample2.Mean, sample1.Variance / sample1.Count, sample2.Variance / sample2.Count,
hypothesizedDifference, alternate);
}
public static void FromDescriptiveResult(this ModelStateDictionary source, DescriptiveResult result)
{
if (result.Succeeded)
{
return;
}
source.AddModelError(string.Empty, string.Join("</br>", result.Errors.Select(d => d.Description)));
}
public async Task <DescriptiveResult> DeleteAsync(int id)
{
var item = await _dbContext.CustomCommands.FirstOrDefaultAsync(d => d.Id == id);
_dbContext.Entry(item).State = EntityState.Deleted;
return(await _dbContext.SaveChangesAsync() > 0
? DescriptiveResult.Success
: DescriptiveResult.Fail().With(string.Empty, "Failed to delete command"));
}
public GeneralHypothesisTest(string firstLabel, DescriptiveResult sample1, string secondLabel,
DescriptiveResult sample2, double hypothesizedDifference = 0,
TwoSampleHypothesis alternate = TwoSampleHypothesis.ValuesAreDifferent)
{
int samples1 = sample1.Count;
int samples2 = sample2.Count;
HypothesizedDifference = Math.Abs(hypothesizedDifference);
var s1 = new SampleInfo
{
Name = firstLabel,
Count = sample1.Count,
Mean = sample1.Mean,
StdDev = sample1.StdDev
};
var s2 = new SampleInfo
{
Name = secondLabel,
Count = sample2.Count,
Mean = sample2.Mean,
StdDev = sample2.StdDev
};
Result = new ComparisonResult
{
FirstSample = s1,
SecondSample = s2,
Hypothesis = alternate,
HypothesizedDifference = HypothesizedDifference
};
if (samples1 < 30 || samples2 < 30)
{
_tTest = new TwoSampleTTest(sample1, sample2, false, HypothesizedDifference, alternate);
Result.Confidence = _tTest.Confidence;
Result.ObservedDifference = _tTest.ObservedDifference;
Result.Significant = _tTest.Significant;
Result.Size = _tTest.Size;
Result.StandardError = _tTest.StandardError;
}
else
{
_zTest = new TwoSampleZTest(sample1, sample2, HypothesizedDifference, alternate);
Result.Confidence = _zTest.Confidence;
Result.ObservedDifference = _zTest.ObservedDifference;
Result.Significant = _zTest.Significant;
Result.Size = _zTest.Size;
Result.StandardError = _zTest.StandardError;
}
}
public async Task <DescriptiveResult> AddAsync(string commandName, string program, string arguments, string permissionName)
{
permissionName = permissionName.ToLowerInvariant();
if (_dbContext.CustomCommands.FirstOrDefault(d => d.PermissionName == permissionName) != null)
{
return(DescriptiveResult.Fail(new DescriptiveError("0",
$"a similar permission name [{permissionName}] already exists")));
}
_dbContext.CustomCommands.Add(new CustomCommand()
{
Program = program,
Argument = arguments,
PermissionName = permissionName,
CommandName = commandName
});
return(await _dbContext.SaveChangesAsync() > 0
? DescriptiveResult.Success
: DescriptiveResult.Fail().With(string.Empty, "Save process failed."));
}
public GeneralHypothesisTest(DescriptiveResult sample1, DescriptiveResult sample2,
double hypothesizedDifference = 0,
TwoSampleHypothesis alternate = TwoSampleHypothesis.ValuesAreDifferent)
: this("first", sample1, "second", sample2, hypothesizedDifference, alternate)
{
}
