I used linear regression to analyze the data of one of my experiments, and used 3 predictors in a first model, added 4 more predictors in a second model, and again 3 more in a third model. The second and third model are significant due to one of the added predictors in each model.

Now I was asked by a reviewer to do a chi-squared test to check whether the change in adjusted R squares between the second and third model (from .08 to .19) is significantly different. I never heard of this test and am unable to contact him/her to ask for more details. I analyzed my data in SPSS and the only option I can find to assess the difference is the F change, which does show a significant F change between model 2 and 3. However, I am by far not an expert on regression analyses and don’t know if using a chi-squared test to compare the goodness of fit would be a better way, or how to do such a test.

I tried to google it, but could not find anything concrete about using the adjusted R squares to compare the models.

I found you can calculate the chi-square of each model and then check if the difference is significant, but I got stuck at calculating the chi-squares of the models.

How can I do this? What would you recommend?

Any help would be much appreciated!

Thank you for your time. ]]>

I recently started working with structural equation modeling. I am doing a study for which I tested a model like this:

Var1 --> var2--> var3 --> var4. All variables are latent variables and have several indicators.

Now, the R² of var3 is +-40% in this case. However, something strange happens when I test the model:

Var1 --> var2 --> var3.

In this case, although the variables BEFORE var3 remain exactly the same, the R² of var3 becomes much smaller (+-28%).

Does anyone know a possible explanation for this? I've already checked whether this is due to missings in var4 but this is not the case. I've also checked this using another software program than the one I normally use (lavaan package in R) and found the same.

Feel free to ask more info if needed. I think this is mainly conceptual though.

Thanks in advance ]]>

Today when I was playing ledo with three dice. I need only two from any single dice. I am new to probability, so I tired to solve by myself the questions arrived in my mind. Can anyone please help with little explanation of following questions.

Lets say each dice is of different color, i.e., Red, Green, and Blue.

1) What is the probability it is 2 given Red dice. P(v=2| Dice=red)

2) What is the probability it is one on every dice. P(R =1, G =1, B = 1) ? ]]>