Final answer:
The average of fatheduc in the sample is computed using only 1,192 observations because of missing data.
Step-by-step explanation:
The reason why only 1,192 observations are used to compute the average of fatheduc in the sample is because of missing data. Missing data refers to the absence or lack of certain observations or information within a dataset. In this case, there may be missing values for the variable fatheduc, which results in a smaller sample size.