title: Error in eval(family$initialize) : y values must be 0 <= y <= 1
body: <p>It was mentioned in the textbook that I need to convert the Satellite data into zeros and ones (if Y=0, then Y=0. But if Y is greater than or equal to 1, then Y=1), but I don't know how to do that. Am I missing something?</p>
  
  <p>Here is my code:</p>
  
  <pre><code>library(icda)
  data(horseshoecrabs)
  crab=horseshoecrabs
  head(crab)
  ??horeshoecrabs
  probit=glm(Satellites ~ Weight, family=binomial(link="probit"), data=horseshoecrabs )
  summary(probit)
  </code></pre>
  
  <p>This problem is from "An introduction to categorical data analysis" 2nd edition problem 3.8 in case that helps. My task is to report the fit for the probit model with weight as the predictor.</p>