I'm trying to convey some findings in which a score from 1-10 seems to predict disease status (binary).

I predict yhat and plot yhat with a quadratic fit against my predictor (score).

It looks accurate but when I add a confidence interval to the quadratic fit, it's VERY narrow. Too narrow for me to believe it.

Does a predicted plot deflate the confidence interval of the original data? If so, does anyone have a suggestion on how I convey my data in a similar format (i.e. for every increase in score, percentage of success increases by y) with a confidence interval?

CI of original data plot (binary outcome):

CI of prediction plot (outcome in percentages):