E Homework: Section 6.3 Confidence Intervals for Question 16, 6.3.20-T HW Score: 52.47%, 14.17 of 27 points Population Pr Part 1 of 3 Points: 0 of 1 A researcher wishes to estimate, with 95% confidence, the population proportion of motor vehicle fatalities that were caused by alcohol-impaired driving. His estimate must be accurate within 5% of the population proportion. (a) No preliminary estimate is available. Find the minimum sample size needed. (b) Find the minimum sample size needed, using a prior study that found that 38% of motor vehicle fatalities that were caused by alcohol-impaired driving. (c) Compare the results from parts (a) and (b). (a) What is the minimum sample size needed assuming that no prior information is available? n= (Round up to the nearest whole number as needed.)