# Multiple regression with dummy variables

I need to calculate MR but my data consists of many dummy variables. I had a question in my survey that asked for the budget/month. But instead of giving the option to fill in a value, I offered ranges (steps of 250, so I have like 0-250; 250.01-500 and so on)

I created dummy variables for these different steps so now I have a total of 6 dummy's and the problem is that I can't calculate the ln-values of these dummy's because all values are either 0 or 1. So any ideas how I can go around this problem?

• I'm not sure I understand what the problem is... why do you want to take the ln of the values exactly? Because the distribution is positively skewed I suspect? Also, to me using 6 dummy variables in this case seems to be something of an overkill. You have the privilege of having your scale start at 0, be ordered, and have equal intervals; with 7 different categories, I just might forget about dummy variables and use it as a continuous variable... May 22, 2013 at 17:23
• I want the ln values so I can check whether they are positively skewed or not actually. How should I use it as a continuous variable thought? Add a column with the median value or something? Like use 125 for each one that is between 0-250 etc? May 22, 2013 at 17:44
• If they're dummies, you don't care if they're skewed or not. (And you don't care about the distribution of predictors in MR, only the distribution of residuals - at least for the purpose of testing assumptions). May 22, 2013 at 18:39
• What's the protocol here, now that I've made my comment into an answer? Do I remove the comment or do I leave it there? Mar 6, 2014 at 16:29