Recent content by mathmathRW

I am doing an independent research project and I have written a logistic regression program in SAS. The percent concordance is 97%, but hardly any variables are significant. Can anyone help me understand why this would happen?

I am doing some research and running a SAS program using logistic regression. The concordance is 99%, but hardly any variables are significant. Can anyone help me understand what this means?

Ok, I have been looking online some more. Should I find ##σ^2(X)## ? It looks like maybe ##∑X_i^2/n=σ^2+[E(X)]^2##. Is that the method of moments estimator? I have found ##σ^2(X)=θ^2/18## and ##∑X_i^2/n=σ^2+[E(X)]^2=θ^2/(2n)##. Am I on the right track?

I calculated ##E(X)=2θ/3## and ##E(X^2)=θ^2/2##. I am not sure how to find ##\sum_{i=1}^n x_i / n##.

Homework Statement Let ##X_1, X_2, ..., X_n## be a random sample from ## f_θ=2x/θ^2## , ##0≤x≤θ##. Find a maximum likelihood estimator for θ. Find the method of moment estimator for θ. The Attempt at a Solution I have already found that the MLE is max{##x_i##}. I just need to find the...

For this particular problem, I think we are just supposed to show that they are what they are.

I have been asked to prove the following limit relations. (a) lim(as x goes to infinity) (b^x-1)/x = log(b) (b) lim log(1+x)/x = 1 (c) lim (1+x)^(1/x) = e (d) lim (1+x/n)^n =e^x Unfortunately, I really have no idea where to start. We have a theorem that says if f(x)=the sum of (c...

Homework Statement I need to prove or disprove this statement: "If all eigenvalues of a diagonalizable matrix A are equal and have the same value c, then A=cI."Homework Equations The Attempt at a Solution I have tried coming up with a diagonalizable matrix that has eigenvalues with all the...