Asample of =25n=25 diners at a local restaurant had a mean lunch bill of $16 with a standard deviation of =$4σ=$4 . we obtain a 95% confidence interval as (14.43,17.57)(14.43,17.57) . which action will not reduce the margin of error? increasing the number of digits for calculating the interval decreasing the confidence level decreasing the sample size sampling from a population with less variability