Young fish in the North Sea.

Samples of 50 Tobis fish, or Sand Eels, were collected at three different locations in the North Sea and the number of one-year-old fish were counted.

Usage

fish_age

Format

A data frame with 300 rows and 3 variables:

year

Year the fish was caught with levels 1997 and 1998.

location

Site the fish was caught with levels A, B and C.

one_year_old

Is the fish one-year-old, yes or no?

Source

Henrik Madsen, Paul Thyregod. 2011. Introduction to General and Generalized Linear Models CRC Press. Boca Raton, FL. ISBN: 978-1-4200-9155-7 Website

Examples

library(dplyr)
library(tidyr)

# Count the number of one-year-old fish at each location.

fish_age %>%
  count(year, location, one_year_old) %>%
  filter(one_year_old == "yes") %>%
  pivot_wider(names_from = location, values_from = n) %>%
  select(-one_year_old)
#> # A tibble: 2 × 4
#>    year     A     B     C
#>   <dbl> <int> <int> <int>
#> 1  1997     9     9     2
#> 2  1998    38    30    15