NHANES 1.7 Creating and summarizing a logical vector

The function is.na() indicates which elements are missing. When applying this function to a vector (such as NHANE$SexAge), a logical vector of the same length as its argument x, containing TRUE for those elements marked NA or and FALSE otherwise.

How many records of the dataset have a missing value for the variable SexAge in the data frame NH_18_69? (Just type the number of missing values)