Run mixed model with age as the random effect
## boundary (singular) fit: see ?isSingular## Linear mixed model fit by REML. t-tests use Satterthwaite's method [
## lmerModLmerTest]
## Formula: TOTALBRAIN ~ cenBPsitLsys + cenAge + (cenAge | HNDid)
## Data: BP
## Control: lmerControl(check.nobs.vs.nRE = "ignore")
##
## REML criterion at convergence: 8443.4
##
## Scaled residuals:
## Min 1Q Median 3Q Max
## -0.0033907 -0.0004224 -0.0000138 0.0003864 0.0039040
##
## Random effects:
## Groups Name Variance Std.Dev. Corr
## HNDid (Intercept) 5.770e+09 7.596e+04
## cenAge 8.890e-06 2.982e-03 -1.00
## Residual 1.548e+02 1.244e+01
## Number of obs: 485, groups: HNDid, 257
##
## Fixed effects:
## Estimate Std. Error df t value Pr(>|t|)
## (Intercept) 9.734e+05 4.738e+03 4.390e+02 205.432 <2e-16 ***
## cenBPsitLsys -8.885e-06 6.329e-02 9.154e+01 0.000 1.000
## cenAge -4.964e-04 2.171e-01 9.154e+01 -0.002 0.998
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Correlation of Fixed Effects:
## (Intr) cnBPsL
## cenBPstLsys 0.000
## cenAge -0.001 -0.134
## convergence code: 0
## boundary (singular) fit: see ?isSingularRun mixed model with intercept as the random effect
## Linear mixed model fit by REML. t-tests use Satterthwaite's method [
## lmerModLmerTest]
## Formula: TOTALBRAIN ~ cenBPsitLsys + cenAge + (1 | HNDid)
## Data: BP
## Control: lmerControl(check.nobs.vs.nRE = "ignore")
##
## REML criterion at convergence: 5800.3
##
## Scaled residuals:
## Min 1Q Median 3Q Max
## -9.977e-07 -2.502e-07 3.250e-09 2.632e-07 1.820e-06
##
## Random effects:
## Groups Name Variance Std.Dev.
## HNDid (Intercept) 5.794e+09 7.612e+04
## Residual 1.283e-03 3.582e-02
## Number of obs: 485, groups: HNDid, 257
##
## Fixed effects:
## Estimate Std. Error df t value Pr(>|t|)
## (Intercept) 9.667e+05 4.695e+03 4.820e+02 205.9 <2e-16 ***
## cenBPsitLsys -2.402e-10 1.823e-04 4.820e+02 0.0 1
## cenAge -2.480e-09 6.252e-04 4.820e+02 0.0 1
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Correlation of Fixed Effects:
## (Intr) cnBPsL
## cenBPstLsys 0.000
## cenAge 0.000 -0.134
## convergence code: 0
## Model is nearly unidentifiable: very large eigenvalue
## - Rescale variables?