A technical agent from the Organization and Methods office of Computex must carry out a study on the schedule of operators assigned to data entry of data. It involves observing these employees at different times of the day and write down their schedule The study must cover 20 days; the service has 15 operators and ten observations will be performed daily on each operator for a total of 3000 observations. The results of this study are divided as follows for the 3000 observations carried out: Productive work Data entry: 1392 observations Work preparation: 432 observations Administrative work: 528 observations Unproductive work Personal occupations: 648 observations a) Estimate by confidence interval the percentage of the productive time of the service of data entry from the Computex company and this with a level of confidence of 90%. b) Estimate by confidence interval and this for an 8-hour working day, the total number of hours lost (non-productive time) by the data entry service data and this with a confidence level of 90%. c) Calculate the margin of error in estimating the proportion of the productive time of the data entry service from Computex. Use trust level specified in a). d) Calculate the sample size necessary to have a margin of error of 1%. Use the confidence level specified in a).