lab_hw7

library(nycflights13)
library(tidyverse)

## -- Attaching core tidyverse packages ------------------------ tidyverse 2.0.0 --
## v dplyr     1.1.4     v readr     2.1.6
## v forcats   1.0.1     v stringr   1.6.0
## v ggplot2   4.0.1     v tibble    3.3.1
## v lubridate 1.9.4     v tidyr     1.3.2
## v purrr     1.2.1     
## -- Conflicts ------------------------------------------ tidyverse_conflicts() --
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()
## i Use the conflicted package (<http://conflicted.r-lib.org/>) to force all conflicts to become errors

library(openintro)

## 载入需要的程序包：airports
## 载入需要的程序包：cherryblossom
## 载入需要的程序包：usdata

babies %>%
  mutate(first_pregnancy = ifelse(parity == 0, "First", "Not First")) %>%
  group_by(first_pregnancy) %>%
  summarize(
    mean_gestation = mean(gestation, na.rm = TRUE),
    median_gestation = median(gestation, na.rm = TRUE),
    sd_gestation = sd(gestation, na.rm = TRUE),
    n = n()
  )

## # A tibble: 2 x 5
##   first_pregnancy mean_gestation median_gestation sd_gestation     n
##   <chr>                    <dbl>            <dbl>        <dbl> <int>
## 1 First                     279.              279         16.6   921
## 2 Not First                 281.              282         14.2   315

Any difference observed is small, indicating only a weak or negligible relationship.