I fitted the following model in r using the lme4 function. The following output is obtained. Is it possible to obtain a graph showing the four different parallel lines? Also, what inferential statistics should I use?
summary(mixedmodel) Linear mixed model fit by REML ['lmerMod'] Formula: (FMI) ~ MVPAper + Age + (1 | Child_ID)
REML criterion at convergence: 34444.6
Scaled residuals:
Min 1Q Median 3Q Max
-1.216 -0.123 -0.093 0.061 51.872
Random effects:
Groups Name Variance Std.Dev.
Child_ID (Intercept) 6.459 2.541
Residual 283.758 16.845
Number of obs: 4048, groups: Child_ID, 1023
Fixed effects:
Estimate Std. Error t value
(Intercept) 2.1850969 0.5697864 3.835
MVPAper 0.0028865 0.0007984 3.615
Age9 0.0908241 0.7482005 0.121
Age12 -0.3519625 0.7478261 -0.471
Age15 -0.4881878 0.7499429 -0.651
Correlation of Fixed Effects:
(Intr) MVPApr Age9 Age12
MVPAper -0.350
Age9 -0.639 -0.040
Age12 -0.652 -0.004 0.498
Age15 -0.671 0.056 0.494 0.496
lmerTestpackage before fitting the model, or comparing nested models using theanova()function, like here: https://stats.stackexchange.com/questions/282646/two-way-repeated-measures-linear-mixed-model/282657#282657 – Mark White Jul 26 '18 at 14:02