Remaining Time: 01:27:40 estion 9 Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. a. When designing a study to determine this population proportion, what is the minimum number you would need to survey to be 90% confident that the population proportion is estimated to within 0.04? The number of drivers surveyed needs to be at least Number b. If it were later determined that it was important to be more than 90% confident and a new survey were commissioned, how would it affect the minimum number you need to survey? Why? The minimum number needed to survey will increase since increasing the confidence level O increases the z-score. The minimum number needed to survey will decrease since increasing the confidence level O decreases the z-score. The minimum number needed to survey will increase since increasing the confidence level decreases the z-score The minimum number needed to survey will decrease since increasing the confidence level O increases the z-score