Hello World! Here’s a Normal Distribution!

November 25, 2017
By

(This article was first published on Dan Garmat's Blog -- R, and kindly contributed to R-bloggers)

This code simulates Normal(0,1), and this visualization shows smaller samples can vary much more than large samples from the true distribution. Maybe it’s not a fascinating picture although there is a deep mystery or two in there. Can we know the truth? Isn’t everything we know based on a sample? Is everything we believe, like these three rnorm(), an incomplete story?

random simulations output

require(tidyverse)
require(tidyr)

random_simulations_1 <- tibble(rnorm(100000)) %>%
  gather %>% 
  rename(distribution = key, observed = value)

random_simulations_2 <- tibble(rnorm(1000)) %>%
  gather %>% 
  rename(distribution = key, observed = value) %>% 
  bind_rows(random_simulations_1)

random_simulations <- tibble(rnorm(10)#, rnorm(100)  
                             #runif(100)#,  
                             #rhyper(100, 100, 50, 10), 
                             #rbinom(100, 10, .5)
                             ) %>%
  gather %>% 
  rename(distribution = key, observed = value) %>% 
  bind_rows(random_simulations_2)

# note we've repeated three times, time for a function
# also note there are other distributions to try this on
# and really, it may ne nice to simulate a few pulls of 
#  the same size

ggplot(random_simulations, aes(observed, 
    fill = as.factor(distribution))) +
  geom_density(alpha = 0.2) + 
  labs(title = "Simulate N(0,1)")

To leave a comment for the author, please follow the link and comment on their blog: Dan Garmat's Blog -- R.

R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: Data science, Big Data, R jobs, visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics (regression, PCA, time series, trading) and more...



If you got this far, why not subscribe for updates from the site? Choose your flavor: e-mail, twitter, RSS, or facebook...

Comments are closed.

Search R-bloggers

Sponsors

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)