dummy variables?



i've been asked , as part of my corrections to use dummy variables yet i'm abit confused about them.

I've got two types of data:

1. dychotomous (yes,no)

2. ordinal (1 ---7) where each value is equally spaced from the next, ie. 7 is 7 times bigger than one....

so where should i use dummy variables? for the dychotomous data? and how?

thanks alot !


oops i meant interval

Avatar for sneaks

You should use dummies where you have dichotomous (e.g. male, female) or categorical data (e.g. married, single, divorced)

In the latter case you always have 1 less dummy than you have categories. So if you have 7 categories, you should have 6 dummy variables to represent it - which is why it is always easier to measure age continuously, rather than in age brackets! (as I found out to my cost)