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On January 28, 1986, a routine launch was anticipated for the Challenger space shuttle. Seventy-three seconds into the flight, disaster happened: the shuttle broke apart, killing all seven crew members on board. An investigation into the cause of the disaster focused on a critical seal called an O-ring, and it is believed that damage to these O-rings during a shuttle launch may be related to the ambient temperature during the launch. The table below summarizes observational data on O-rings for 23 shuttle missions, where the mission order is based on the temperature at the time of the launch.

Usage

orings

Format

A data frame with 23 observations on the following 4 variables.

mission

Shuttle mission number.

temperature

Temperature, in Fahrenheit.

damaged

Number of damaged O-rings (out of 6).

undamaged

Number of undamaged O-rings (out of 6).

Examples


library(dplyr)
library(forcats)
library(tidyr)
library(broom)

# This is a wide data frame. You can convert it to a long
# data frame to predict probability of O-ring damage based
# on temperature using logistic regression.

orings_long <- orings %>%
  pivot_longer(cols = c(damaged, undamaged), names_to = "outcome", values_to = "n") %>%
  uncount(n) %>%
  mutate(outcome = fct_relevel(outcome, "undamaged", "damaged"))

orings_mod <- glm(outcome ~ temperature, data = orings_long, family = "binomial")
tidy(orings_mod)
#> # A tibble: 2 × 5
#>   term        estimate std.error statistic   p.value
#>   <chr>          <dbl>     <dbl>     <dbl>     <dbl>
#> 1 (Intercept)   11.7      3.30        3.54 0.000403 
#> 2 temperature   -0.216    0.0532     -4.07 0.0000477