Past exam of the mathematics course of the University of Cambridge / 2022 / ii / Paper 1 / 13J / a

The first command counts missing values in every column: there are $177$ missing ages and $687$ missing cabin entries, with none in the other variables. The next command deletes Cabin. The final command replaces every missing age by the mean of the observed ages, using na.rm = TRUE so missing entries do not contaminate that mean.