Dear Statalist,
I have found the following example and interpretation of a categorical by categorical linear interaction but have trouble following the gender#prog explanation. Here is the source: https://stats.oarc.ucla.edu/stata/se...actions-stata/ (towards the end of the page, heading categorical by categorical).
Previously, I thought one interprets the interactions as follows: 1 and 0; 0 and 1; 1 and 1 (compared to 0 and 0).
In the example below, the reference gender is female, and the reference for prog is reading.
To begin:
male | -.3354569 in my opinion is when male = 1 and prog = 0 (so reading)
Under prog:
jog: when jog = 1 and male = 0 (so female) vs. female and reading
swim: when swim = 1 and male = 0 (so female) vs. female and reading
gender#prog:
male#jog when male = 1 and jog = 1 vs. Male = 0 (so female) and jog=0 (so reading)
male#swim when male = 1 and swim = 1 vs. Male = 0 (so female) and swim=0 (so reading)
As per the page:
Q1: male | -.3354569 is the additional weight loss over women by reading? I.e., men gain more (because of a negative loss) by reading than women?
Q2: Are my interpretation of prog and prog##gender correct?
I have trouble understanding the additional sentence in gender#prog: Also, the jogging effect (jogging – reading) for males versus the jogging effect for females. (and for swimming).
Does this mean both sentences happen simultaneously?
Thank you so much in advance!
I have found the following example and interpretation of a categorical by categorical linear interaction but have trouble following the gender#prog explanation. Here is the source: https://stats.oarc.ucla.edu/stata/se...actions-stata/ (towards the end of the page, heading categorical by categorical).
Previously, I thought one interprets the interactions as follows: 1 and 0; 0 and 1; 1 and 1 (compared to 0 and 0).
In the example below, the reference gender is female, and the reference for prog is reading.
To begin:
male | -.3354569 in my opinion is when male = 1 and prog = 0 (so reading)
Under prog:
jog: when jog = 1 and male = 0 (so female) vs. female and reading
swim: when swim = 1 and male = 0 (so female) vs. female and reading
gender#prog:
male#jog when male = 1 and jog = 1 vs. Male = 0 (so female) and jog=0 (so reading)
male#swim when male = 1 and swim = 1 vs. Male = 0 (so female) and swim=0 (so reading)
Code:
-------------------------------------------------------------------------------------
| Robust
loss | Coefficient std. err. t P>|t| [95% conf. interval]
--------------------+----------------------------------------------------------------
gender |
male | -.3354569 .7527049 -0.45 0.656 -1.812731 1.141818
|
prog |
jog | 7.908831 .7527049 10.51 0.000 6.431556 9.386106
swim | 32.73784 .7527049 43.49 0.000 31.26057 34.21512
gender#prog |
male#jog | 7.818803 1.064486 7.35 0.000 5.729621 9.907985
male#swim | -6.259851 1.064486 -5.88 0.000 -8.349033 -4.170669
- male: the simple effect of males for Djog=0,Dswim=0 (i.e., the male – female weight loss in the readinggroup).
- b^2 jog: the simple effect of jogging when Dmale=0 (i.e., the difference in weight loss between jogging versus reading for females).
- b^3 swim: the simple effect of swimming when Dmale=0 (i.e., the difference in weight loss between swimming versus reading for females).
- b^4 male#jog: the interaction of Dmale and Djog, the male effect (male – female) in the jogging condition versus the male effect in the reading condition. Also, the jogging effect (jogging – reading) for males versus the jogging effect for females.
- b^5 male#swim: the interaction of Dmale and Dswim, the male effect (male – female) in the swimming condition versus the male effect in the reading condition. Also, the swimming effect (swimming- reading) for males versus the swimming effect for females.
Q1: male | -.3354569 is the additional weight loss over women by reading? I.e., men gain more (because of a negative loss) by reading than women?
Q2: Are my interpretation of prog and prog##gender correct?
I have trouble understanding the additional sentence in gender#prog: Also, the jogging effect (jogging – reading) for males versus the jogging effect for females. (and for swimming).
Does this mean both sentences happen simultaneously?
Thank you so much in advance!
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