Start by loading the NHANES data like in the previous exercise.

library(NHANES)
data(NHANES)

1. Compute the average and standard deviation of the BPSysAve variable for females, but for each age group separately rather than a selected decade as in question 1. Note that the age groups are defined by AgeDecade. Hint: rather than filtering by age and gender, filter by Gender and then use group_by. Store the result in a data frame summary_female with a mean and a sd column for the average and standard deviation respectively.

2. Repeat exercise 1 for males. Store the result in summary_male

3. We can actually combine both summaries for exercises 1 and 2 into one line of code. This is because group_by permits us to group by more than one variable. Obtain one big summary table using group_by(Gender, AgeDecade). Store the result in a data frame summary_complete.