Issue with number of days for previous 3 weeks or 7 days analyses

[jarvisc1]

We are subtracting the number of days from the latest database date for many of the analyses.

For seven days we've been subtracting the 7 and then for 3 week we've been doing 21.

This give 8 days and 22 days. As follows

start_date <- date("2019-01-20")-3
seq(start_date, date("2019-01-20"), 1)
length(seq(start_date, date("2019-01-20"), 1))

So we need to subtract 6 and 20 days to get previous 7 or 21 days.