Hello! I am trying to run a paired t test on a subset of data, although it is giving me this error message:

intxSubB <- t.test(Intake ~ Day, data = intxTestsubB.long, paired = TRUE)

Error in complete.cases(x, y) : not all arguments have the same length

My a sample of my subset is:

With an earlier column having PCB, Sex, and Animal ID (just would not fit in the photo).

I have a feeling the error messages mean that the two groups (Day 2 and Day 8) are uneven, which is true as Day 8 has NA, however I was wondering if there is a way to conduct the paired t test regardless of this missing data point.

Thank you!