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Started Oct 25, 2011 0 Replies 0 Likes

Hi there-- Thanks in advance for helping out a newbie. I presented an OLS to my boss and he said that though the residual vs. Y value plot did not show heteroskedasticity that I needed to use WLS and…Continue

Started this discussion. Last reply by K.Kalyanaraman Jul 28, 2011. 13 Replies 0 Likes

Hi -- I know this is a basic question. I'm learning and thanks for all your help (in advance.) I have one variable and it's an indicator variable. Respondents get a 1 if they are in one category; 2…Continue

Started this discussion. Last reply by Berkeley Sarah Aug 30, 2010. 2 Replies 0 Likes

Hi there,My work has taken me into network questions which is new to me. I've found that some of my intuition is not appropriate here so I'm turning to you all for assistance.Here's what I have: 1.…Continue

Started this discussion. Last reply by Laurence Moseley May 18, 2010. 9 Replies 0 Likes

Hello --I am a graduate student who is just setting off on her career in analytics and I am delighted there is a community like this one. Now, my first question!I have a series of variables on which…Continue

Berkeley Sarah's discussion was featured### weighting residuals after using WLS?

Hi there-- Thanks in advance for helping out a newbie. I presented an OLS to my boss and he said that though the residual vs. Y value plot did not show heteroskedasticity that I needed to use WLS and gave me a matrix of weights. Did it and the fitted Y's did not change much at all compared to OLS. The residual plot also did not show heterosked. Then my boss said I had to weight the residuals after WLS. This seems odd to me. What do you think? Thanks,Sarah See More

Oct 25, 2011

Berkeley Sarah posted a discussion### weighting residuals after using WLS?

Hi there-- Thanks in advance for helping out a newbie. I presented an OLS to my boss and he said that though the residual vs. Y value plot did not show heteroskedasticity that I needed to use WLS and gave me a matrix of weights. Did it and the fitted Y's did not change much at all compared to OLS. The residual plot also did not show heterosked. Then my boss said I had to weight the residuals after WLS. This seems odd to me. What do you think? Thanks,Sarah See More

Oct 25, 2011

K.Kalyanaraman replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"That is true. The two tests, test for proportion and Chisquare goodness of fit are one and the same in these cases.
P = 0.5
Assume sample size 100 and males are 45 and females are 55.
Test for proportion Z =…"

Jul 28, 2011

Ralph Winters replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"There are two forms of the chi-square test. One is of them is the one-way (or goodness of fit) test. In this case, the goal is to determine whether a set of frequencies or proportions is similar to a hypothesized set of…"

Jul 28, 2011

Berkeley Sarah replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"Ok then I must be confused. I thought a chi-squared test required two variables. If you can clarify, I'd appreciate it."

Jul 28, 2011

Ralph Winters replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"Actually both answers are correct depending upon the assumptions: You can use a Z-test if you assume the probability of success is ~ .5 (coin flip) and you have a high number of responses. If you are not willing to make those assumptions, use…"

Jul 28, 2011

Berkeley Sarah replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"Thanks but I think I need a proportions test because I do not have two categorical variables. I have one categorical variable with two categories."

Jul 28, 2011

K.Kalyanaraman replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"The two groups are to be compared for gender, a categorical variable in Nominal scale. The associated hypothesis may be any of the following depending upon observed proportions of male/female and the problem. If the problem is to compare the general…"

Jul 28, 2011

Amanpreet Singh replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"You can compare the means of 2 groups using a simple T-test (look up the ratio in the table of significance to decide if it is significant enough for chance findings)
"

Jul 27, 2011

Abhinav Jain replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"What your trying to do is known as "Establishing relationship between two categorical variables" in the language of statistics.
Chi-square test is very popular technique to perform this test. "

Jul 27, 2011

Berkeley Sarah replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"Thanks. This would be akin to a gender variable. 0 if male; 1 if female. I'm interested to know if the difference between the percent male and female is statistically significant or could be attributed to chance. I think I need a test of…"

Jul 27, 2011

Berkeley Sarah replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"Thanks. This would be akin to a gender variable. 0 if male; 1 if female. I'm interested to know if the difference between the percent male and female is statistically significant or could be attributed to chance. I think I need a test of…"

Jul 27, 2011

K.Kalyanaraman replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"Please look at your question. There are two categories and you want to see if there is any difference between them, but with respect to what! Please say more about what you measure with the items in each group."

Jul 27, 2011

Amanpreet Singh replied to Berkeley Sarah's discussion One indicator variable, two categories, statistically significant test?

"Im sorry but just to make things a bit more clear , you are trying to differentiate between 2 variables or are you trying to find if one variable is statistically significant in predicting the change in the other variable (from your post's…"

Jul 26, 2011

Berkeley Sarah posted a discussion### One indicator variable, two categories, statistically significant test?

Hi -- I know this is a basic question. I'm learning and thanks for all your help (in advance.) I have one variable and it's an indicator variable. Respondents get a 1 if they are in one category; 2 if they are in the other. I want to determine if the number of 1 is statistically different than 2. What test do I use? Thanks,SarahSee More

Jul 26, 2011

Berkeley Sarah replied to Berkeley Sarah's discussion Social Network Technique

"Thank you. They, however, are using one data source -- The Framingham Heart Study."

Aug 30, 2010

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