Answer
$n=19$
Work Step by Step
Since confidence level is 0.98 so we go to t- distribution table to find critical value ,when level of confidence is 0.99 critical value is2.575 so we have to look for the closest number to it in the t -dist. table so the answer is 2.552 when d.f is 18 so n is d.f+1 so N is 19
