#Point-biserial: We can do that with our dichotomous Gender and Cancer

#install.packages("ltm")
library(ltm)

## Loading required package: msm

## 
## Attaching package: 'msm'

## The following object is masked from 'package:boot':
## 
##     cav

## Loading required package: polycor

## 
## Attaching package: 'polycor'

## The following object is masked from 'package:psych':
## 
##     polyserial

## 
## Attaching package: 'ltm'

## The following object is masked from 'package:psych':
## 
##     factor.scores

biserial.cor(Wk08a$Cancer, Wk08a$Gender, use = "all.obs", level = 2)

## [1] 0.4601389