Probenecid is a drug used by some athletes to prevent the excretion of other substances into urine, thus lowering their detectable concentrations. a scientist makes three measurements of a urine sample known to contain probenecid and obtains a confidence interval of 11.8±0.5 mg/l at the 95% confidence level. what would happen to the confidence interval at the same confidence level if the number of measurements is increased to 10 assuming the standard deviation remains the same?