Question 1178700
The 90% confidence interval is given by 

{{{p[1] +- t[0.95]*sqrt((p[1]*(1-p[1]))/n)}}}

= {{{66/82 +- t[0.95]*sqrt(((66/82)*(16/82))/82)}}}

= {{{66/82 +- 1.664*sqrt(((66/82)*(16/82))/82)}}}

= [0.732, 0.878], with the endpoints rounded to 3d.p.

The t-distribution probabilities were taken from https://stattrek.com/online-calculator/t-distribution.aspx.