Again, start by loading the NHANES data like in the previous exercise.
library(NHANES)
data(NHANES)
For males between the ages of 40-49, compare systolic blood pressure
across race as reported in the Race1 variable. Order the resulting
table from lowest to highest average systolic blood pressure.
Store the result in a data frame summary_by_race. It should have a
Race1 and a mean_BP column.