9: Sampling

Based on Chapter 7 of ModernDive. Code for Quiz 11.

  1. Load the R package we will use.
library(tidyverse)
library(moderndive) #install before loading
  1. Quiz questions

Question:

7.2.4 in Modern Dive with different sample sizes and repetitions

Modify the code for comparing differnet sample sizes from the virtual bowl

Segment 1: sample size = SEE QUIZ

1.a) Take SEE QUIZ samples of size of SEE QUIZ instead of 1000 replicates of size 25 from the bowl dataset. Assign the output to virtual_samples_SEE QUIZ

???  <- bowl  %>% 
rep_sample_n(size = ???, reps = ???)

1.b) Compute resulting SEE QUIZ replicates of proportion red

??? <- ??? %>% 
  group_by(???) %>% 
  ???(red = sum(color == "red")) %>% 
  ???(prop_red = red / ???)

1.c) Plot distribution of virtual_prop_red_SEE QUIZ via a histogram

use labs to

ggplot(virtual_prop_red_SEE QUIZ, aes(x = ???)) +
  ???(binwidth = 0.05, boundary = 0.4, color = "white") +
  labs(x = "???", title = "???") 

Segment 2: sample size = SEE QUIZ

2.a) Take SEE QUIZ samples of size of SEE QUIZ instead of 1000 replicates of size 50. Assign the output to virtual_samples_SEE QUIZ

???  <- bowl  %>% 
rep_sample_n(size = ???, reps = ???)

2.b) Compute resulting SEE QUIZ replicates of proportion red

??? <- ??? %>% 
  group_by(???) %>% 
  ???(red = sum(color == "red")) %>% 
  ???(prop_red = red / ???)

2.c) Plot distribution of virtual_prop_red_SEE QUIZ via a histogram

use labs to

ggplot(virtual_prop_red_SEE QUIZ, aes(x = ???)) +
  ???(binwidth = 0.05, boundary = 0.4, color = "white") +
  labs(x = "???", title = "???") 

Segment 3: sample size = SEE QUIZ

3.a) Take SEE QUIZ samples of size of SEE QUIZ instead of 1000 replicates of size 50. Assign the output to virtual_samples_SEE QUIZ

???  <- bowl  %>% 
rep_sample_n(size = ???, reps = ???)

3.b) Compute resulting SEE QUIZ replicates of proportion red

??? <- ??? %>% 
  group_by(???) %>% 
  ???(red = sum(color == "red")) %>% 
  ???(prop_red = red / ???)

3.c) Plot distribution of virtual_prop_red_SEE QUIZ via a histogram

use labs to

ggplot(virtual_prop_red_SEE QUIZ, aes(x = ???)) +
  ???(binwidth = 0.05, boundary = 0.4, color = "white") +
  labs(x = "???", title = "???") 

Calculate the standard deviations for your three sets of SEE QUIZ values of prop_red using the standard deviation

n = SEE QUIZ

???  %>% 
  summarize(sd = sd(prop_red))

n = SEE QUIZ

???  %>% 
  summarize(sd = sd(prop_red))

n = SEE QUIZ

???  %>% 
  summarize(sd = sd(prop_red))

The distribution with sample size, n = ???, has the smallest standard deviation (spread) around the estimated proportion of red balls.