Hi Oscar,
You can copy the formula for
Cronbach's alpha in Mathematica almost verbatim from Wikipedia.
It's used for consistency checks in psychometric tests, so we'll use the employee attitude example data set.
data = N@ExampleData[{"Statistics", "EmployeeAttitude"}];
Then we just copy the formula.
k = Length@First@data;
x = Total /@ data;
a = k/(k - 1) (1 - Sum[Variance@data[[All, i]], {i, k}]/Variance@x)
0.843143
To see how similar the formula is in Mathematica to the form on Wikipedia, we can view the Mathematica version in TraditionalForm.
