I'm running a regression to see if theres a positive or negative relationship between cvdrst and smkcigst, but I'm not sure how to interpret this regression also why is the data for smkcigst NA, even though the dataset has no NAs for it and instead has 1 for all observations. Please help! Does this regression show that there is a positive or a negative relationship between the two variables?! I'm also having trouble greating plots because the plot only shows 2 points, please help me write a code to plot this regression, thanks!

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  • $\begingroup$ Notice the message above your output table: "Coefficients: 1 not defined because of singularities". You do not have an estimate for that variable. This happened because you can express one of your columns as a linear combination of some others. You can also see very high standard errors in your table which even if you didn't have perfect multicollinearity would show something is wrong. To answer your question though, if you did have a coefficient for smkcigst_a, a positive coefficient would mean there is a positive association between the response and smkcigst_a. $\endgroup$
    – fmtcs
    May 14 at 8:18
  • $\begingroup$ Actually the NA happens because "smkcigst has 1 for all observations". This means that smkcigst is indistinguishable from the intercept. How do you expect to observe a correlation between a variable that is always 1 and another variable? Note: As @fmtcs points out, in general NA's in the summary table indicate exact linear dependency between predictors. But in your case, we can identify the cause even more precisely. $\endgroup$
    – dipetkov
    May 14 at 8:46
  • $\begingroup$ @dipetkov Whoops, I missed that in the original post. $\endgroup$
    – fmtcs
    May 14 at 9:26


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