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Questions?

Clone a repo + start a new project

Go to the ae-08-[GITHUB USERNAME] repo, clone it, and start a new project in RStudio. See the Lab 01 for more detailed instructions about cloning a repo and starting a new project.

Configure git

Run the following code to configure Git. Fill in your GitHub username and the email address associated with your GitHub account.

library(usethis)
use_git_config(user.name = "your github username", user.email ="your email")
library(tidyverse)

Use R as a calculator for the exercises in this AE.

Warm-up

Suppose in a class that 30% of students were Pratt students and 70% were Trinity. 10% of Pratt students are vegetarian and 5% of Trinity students are vegetarian.

Exercise 1

What is the probability that a randomly selected student in this class is vegetarian?

Exercise 2

Given that a student is vegetarian, what is the probability that they are in Pratt?

The Abbott Alinity Test

The global coronavirus pandemic illustrates the need for accurate testing of COVID-19, as its extreme infectivity poses a significant public health threat. Due to the time-sensitive nature of the situation, the FDA has enacted emergency authorization of a number of serological tests for COVID-19. Full details of these tests may be found on its website here.

The Abbott Alinity test has an estimated sensitivity of 100% and specificity of 99%.

Exercise 3

Suppose the prevalence of COVID-19 in the general population is 2%. What are the positive and negative predictive values of the Abbott Alinity test?

Exercise 4

Now suppose the prevalence of COVID-19 in the general population is 8%. Repeat the same calculations as in Exercise 3. Can you reuse code from Exercise 3 somehow?

Exercise 5

In the context of COVID-19, would you prefer to have a test with perfect sensitivity and good specificity or would you rather have a test with perfect specificity and good sensitivity? Explain your answer.