Hi All,
I am trying to do pairwise comparisons to see the difference of means within each two groups (I have four groups totally). But in the SAS output below, the last column shows which group comparison is significant or not. But I want to get the p-value of the last column, not just star signs. Any idea?
Here is my output Table:
Comparisons significant at the 0.05 level are indicated by ***. | ||||
group | Difference | Simultaneous 95% Confidence Limits |
| |
(1) Toddler - (2) Young | 8.862 | 0.592 | 17.131 | *** |
(1) Toddler - (3) Child | 16.756 | 8.674 | 24.838 | *** |
(1) Toddler - (4) Teen | 20.183 | 11.744 | 28.621 | *** |
(2) Young - (1) Toddler | -8.862 | -17.131 | -0.592 | *** |
(2) Young - (3) Child | 7.894 | 0.574 | 15.214 | *** |
(2) Young - (4) Teen | 11.321 | 3.608 | 19.033 | *** |
(3) Child - (1) Toddler | -16.756 | -24.838 | -8.674 | *** |
(3) Child - (2) Young | -7.894 | -15.214 | -0.574 | *** |
(3) Child - (4) Teen | 3.427 | -4.084 | 10.938 |
|
(4) Teen - (1) Toddler | -20.183 | -28.621 | -11.744 | *** |
(4) Teen - (2) Young | -11.321 | -19.033 | -3.608 | *** |
(4) Teen - (3) Child | -3.427 | -10.938 | 4.084 |
|
Here is my code:
proc anova data=combine;
class group;
model variable = group;
means group / BON;
run;
proc glm data=combine;
class group;
model variable = group;
means group / bon;
run;
Thanks,
C
use
lsmeans group / pdiff adjust=bon; /* or another adjust= option */
Complete example:
proc glm data=sashelp.cars;
class type;
model mpg_city = type;
lsmeans type / pdiff adjust=bon;
run;
The doc shows many ways to adjust the p-values for multiplicity. I like Bonferonni and SIMULATE.
Hi Rick,
Yes, I got this way before, but in this way, SAS outputs P-value table in as a matrix (as shown below). Then I have to write a long code to reorganize the p-values along with group comparison so they can display as one column (as the last column in the table shown in my question). I think that's a complex way....
Least Squares Means for effect group | ||||
i/j | 1 | 2 | 3 | 4 |
1 |
| 0.0047 | <.0001 | <.0001 |
2 | 0.0047 |
| 0.0045 | 0.0001 |
3 | <.0001 | 0.0045 |
| 0.2270 |
4 | <.0001 | 0.0001 | 0.2270 |
|
Any way to show the p_values in the last column instead of star signs like in the below table directly?
Comparisons significant at the 0.05 level are indicated by ***. | ||||
group | Difference | 95% Confidence Limits |
| |
(1) Toddler - (2) Young | 8.862 | 2.732 | 14.992 | *** |
(1) Toddler - (3) Child | 16.756 | 10.764 | 22.747 | *** |
(1) Toddler - (4) Teen | 20.183 | 13.927 | 26.438 | *** |
(2) Young - (1) Toddler | -8.862 | -14.992 | -2.732 | *** |
(2) Young - (3) Child | 7.894 | 2.467 | 13.320 | *** |
(2) Young - (4) Teen | 11.321 | 5.604 | 17.038 | *** |
(3) Child - (1) Toddler | -16.756 | -22.747 | -10.764 | *** |
(3) Child - (2) Young | -7.894 | -13.320 | -2.467 | *** |
(3) Child - (4) Teen | 3.427 | -2.141 | 8.995 |
|
(4) Teen - (1) Toddler | -20.183 | -26.438 | -13.927 | *** |
(4) Teen - (2) Young | -11.321 | -17.038 | -5.604 | *** |
(4) Teen - (3) Child | -3.427 | -8.995 | 2.141 |
|
Thanks,
C
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