title: How to calculate 95% Confidence intervals for categorical data (Daily, Occasionally, Never)
body: <p>I asked a random selection of people the following question "How often do you smoke?". The answer categories were as follows: 1. Daily 2. Occasionally or 3. Never .  I have details about the respondents such as age and gender.  </p>
  
  <p>The results are as follows: </p>
  
  <p>10% of respondents smoke daily. 
  5% smoke occasionally.
  85% Never smoke. </p>
  
  <p>My question is:</p>
  
  <p>Is it possible to calculate confidence intervals around this categorical data? i.e. 10% of respondents smoke daily, lower CI= 8% upper Ci=12%.</p>
  
  <p>I am using R, SAS and python to investigate this. </p>
  
  <p>I have sourced this SAS code:</p>
  
  <pre><code>     proc freq data=smoking_data;
       tables smoke / binomial(level='1'); /*Daily*/
  
       tables smoke / binomial(level='2'); /*Occasionally*/
  
       tables smoke / binomial(level='3'); /*Never*/
  
      run;
  </code></pre>
  
  <p>This appears to work but I am unsure if Binomial is correct to use with categorical data.</p>
  
  <p>Thank you for any help in advance</p>