title: Logistic Curve Problems
body: <p>I am trying to plot a logistic curve using ggplot but I keep getting a straight line on my graph (as opposed to a curved line). My dependent variable (Y) is binary and my independent variable (X) is continuous. This is the script I am using:</p>
  
  <pre><code> ggplot(data=ice, aes(X,Y)) + 
   geom_point(position=position_jitter(h=.01, w=.1)) + 
   geom_smooth(method='glm', method.args = 
   list(start=c(tau=0.2,Vmax=2)), 
   se=TRUE) + 
   labs(title='Title') + 
   xlab('X') + 
   ylab('Y')
  </code></pre>
  
  <p>What is strange is that the following code used to work: </p>
  
  <pre><code> ggplot(data=ice, aes(X,Y)) + 
   geom_point(position=position_jitter(h=.01, w=.1)) + 
   stat_smooth(method='glm', family="binomial") + 
   labs(title='Title') + 
   xlab('X') + 
   ylab('Y')
  </code></pre>
  
  <p>but I now get the error:</p>
  
  <pre><code>Error: Unknown parameters: family
  </code></pre>
  
  <p>What is missing from my new code?</p>