patitooo
Hello everybody,
I have a simulation study and I try to generate irt data with a program called WINGEN. I want to generate dichotomously scored, normal distributed and unidimensional data.
And my number of examinees are 10000, number of items 40 and my irt model is 2PLM. WINGEN asks me about the parameters a and b. The distribution, mean and std of the parameters.I enter normal distribution option for a and b and for a parameter mean=1 std=0.05, for b parameter mean=0 std=0.05. But these way, my data did not unidimensional. I want to ask you, for a unidimensional data, what is the a and b paramaters? Please help me, I'm very new in IRT
I have a simulation study and I try to generate irt data with a program called WINGEN. I want to generate dichotomously scored, normal distributed and unidimensional data.
And my number of examinees are 10000, number of items 40 and my irt model is 2PLM. WINGEN asks me about the parameters a and b. The distribution, mean and std of the parameters.I enter normal distribution option for a and b and for a parameter mean=1 std=0.05, for b parameter mean=0 std=0.05. But these way, my data did not unidimensional. I want to ask you, for a unidimensional data, what is the a and b paramaters? Please help me, I'm very new in IRT