title: Scatterplot in RStudio with ggplot function
body: <p>I'm trying to see that there is any correlation between the education level and cholesterol awareness using data from the Behavioral Risk Factor Surveillance System for 2013 dataset. The contents of the data can be checked from the link down below:
  <a href="https://d18ky98rnyall9.cloudfront.net/_e34476fda339107329fc316d1f98e042_brfss_codebook.html?Expires=1541203200&amp;Signature=WYq5YJFg5WgVOFV4dWPV~pPtu-31ubNEVxEYlNliJZpqZYXfZ741WN9n~RC~kcF0gE6AdxzzNFbiA7nv5DtQsxeWWs1Y9obwadm2PjV8eO~W0TI0YtyU~vmaWgozEkfbzIB17LP0MFY-dUffEsyb29~~JWYnQXHAZXdm-n5q108_&amp;Key-Pair-Id=APKAJLTNE6QMUY6HBC5A##sleptim1" rel="nofollow noreferrer">https://d18ky98rnyall9.cloudfront.net/_e34476fda339107329fc316d1f98e042_brfss_codebook.html?Expires=1541203200&amp;Signature=WYq5YJFg5WgVOFV4dWPV~pPtu-31ubNEVxEYlNliJZpqZYXfZ741WN9n~RC~kcF0gE6AdxzzNFbiA7nv5DtQsxeWWs1Y9obwadm2PjV8eO~W0TI0YtyU~vmaWgozEkfbzIB17LP0MFY-dUffEsyb29~~JWYnQXHAZXdm-n5q108_&amp;Key-Pair-Id=APKAJLTNE6QMUY6HBC5A##sleptim1</a></p>
  
  <p>There are two variables what I used for EDA: "educa"(Education Level) and "cholchk"(How Long Since Cholesterol Checked). And this is the code what I created:</p>
  
  <pre><code>&gt; q1 &lt;- select(brfss2013, cholchk, educa) %&gt;%
          filter(!is.na(cholchk), !is.na(educa))
  
  &gt; q1 %&gt;% group_by(cholchk) %&gt;%    summary(count=n())
  
  &gt; ggplot(data = q1, aes(x = educa, y = cholchk)) +
      geom_point(shape=1) +
      geom_smooth(method=1) +
      xlab("educa = Education Level") +
      ylab ("cholchk: How Long Since Cholesterol Checked")
  </code></pre>
  
  <p>The graph was successfully created. But all dots on the graph are spread at regular intervals(?), so it's unable to check correlation. Could you give me some advice to get a better look than this?</p>
  
  <p><a href="https://i.stack.imgur.com/kh761.png" rel="nofollow noreferrer">scatterplot image</a>  </p>
  
  <p>I don't know how to upload ".RData" file on my question. So this is the best I can do.</p>
  
  <p>cholchk<br>
   Within past year   :321955<br>
   Within past 2 years: 49354<br>
   Within past 5 years: 29870<br>
   5 or more years ago: 15683</p>
  
  <p>educa<br>
   Never attended school or only kindergarten                  :   463<br>
   Grades 1 through 8 (Elementary)                             : 10189<br>
   Grades 9 though 11 (Some high school)                       : 21173<br>
   Grade 12 or GED (High school graduate)                      :117152<br>
   College 1 year to 3 years (Some college or technical school):113993<br>
   College 4 years or more (College graduate)                  :153892</p>