library(dplyr)
duck <- data.frame(n = c(48,  47,  41,  39,  32,  28,  25,  24),
                  died = c(1, 2, 2, 5, 4, 3, 1, 1),
                  lived = c(47,  45,  39,  34,  28,  25,  24,  23))

# you can add variables with mutate, and you can use the new variables
#  below in the same mutate statement to create other variables 
# Add what you need to 'duck' with additional lines to the 'mutate' statement
#  that replace the '...' currently there
# NOTE: you can learn more about dplyr on datacamp and the web.
#   '%>%' pipes the data into the statements that follow
duck <- duck %>% 
  mutate(p_hat = lived/n,
         var_p_hat = p_hat * (1 - p_hat) / n,
         ...)

# use the 'summarise' function from 'dplyr' to calculate key totals
totals <- duck %>%
  summarise(n = sum(n),
            died = sum(died),
            lived = sum(lived))

# complete the 'mutate' statement to calculate necessary variables on totals
#  by replacing the '...' currently there with the necessary commands
totals <- totals %>%
  mutate(...)