topic Re: interpretation of coefficients using standard deviation in Statistical Procedures

interpretation of coefficients using standard deviation

somebody — Wed, 11 Apr 2018 15:12:47 GMT

I am trying to analyse my regression results and I need to interpret the economic magnitude of specific independent variable in terms of its standard deviation.

For example: Y = a + bX + u

In general, one can say that when X increases by one unit, Y is expected to increase by 'b' value.

Alternatively, one can say that when X increases by one standard deviation, Y is expected to increase by 'some' value.

How to obtain this 'some' value in SAS?

To my understanding, formulary, for std change in X, Y would change : [b*std(y)] / mean(y). I am not sure if this formula is correct.

Re: interpretation of coefficients using standard deviation

art297 — Wed, 11 Apr 2018 16:58:24 GMT

If N is the number of SD from the mean of X wouldn't you want:

a + bX* (meanX+N*sdX)

an Example:

data have;
  input x y;
  cards;
1 3
2 6
3 9
4 12
5 14
6 18
7 20
8 24
9 26
10 28
;

proc reg data=have;
  model  Y=X;
run;

proc means data=have;
  var x y;
run;

results in: MeanX=5.5 sdX=3.02765 bX=2.83636 a=.4

Thus, 2 sd above mean would be x=11.5553

.4 +2.83636*11.553=33.17499

Art, CEO, AnalystFinder.com

Re: interpretation of coefficients using standard deviation

PaigeMiller — Wed, 11 Apr 2018 17:02:25 GMT

Alternatively, one can say that when X increases by one standard deviation, Y is expected to increase by 'some' value.

How to obtain this 'some' value in SAS?

Y increases by b * (one standard deviation of X)