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Summary statistics by group

Building on the last exercise, in this exercise you will continue to use the dplyr::summarise() and summarise(across(everything(), list())) syntax with the group_by() function to compute custom statistics for specific variables by groups of interest such as the sex and adult categories.

The abaloneKeep dataset and dplyr package are already loaded for you.

This exercise is part of the course

R For SAS Users

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Exercise instructions

  • Get statistics by grouping variable using summarise() and group_by().
  • Get median, 25th and 75th percentiles for whole weight by adult and name output as median_wweight, q1_wweight and q3_wweight.
  • Get mean and sd for height and diameter by sex.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

# Get median, 25th, 75th percentiles for wholeWeight by adult
abaloneKeep %>% 
  group_by(___) %>%
  select(___) %>%
  summarise(median_wweight = median(___),
            q1_wweight = quantile(___, probs = ___),
            q3_wweight = quantile(___, probs = ___))

# Get mean and sd for height and diameter by sex
abaloneKeep %>%
  group_by(___) %>%
  select(___) %>%
  summarise(across(everything(),list(___ = ~ mean(.x),
                                     ___ = ~ sd(.x))))
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