Researchers observed 50 random people brush their teeth and recorded the number of seconds each person spent brushing From the sample they found a mean time of 41 7 seconds Further their calculations revealed that this estimate is within a margin of error of 2 15 from the true average time that all people spend brushing their teeth Write the interval estimate that will estimate the true average time that people spend brushing their teeth Write your answer in interval notation Write your answer using inequality notation ft