Aparticular county health department experimented with a flexible four-day workweek. for a year, the department recorded the mileage driven by 11 field workers on an ordinary five-day workweek. then, it changed to a flexible four-day workweek and recorded the mileage for another year for the same 11 field workers. test the hypothesis that the five-day workweek has a greater average mileage. assume all conditions are satisfied in this problem. the data set used for this problem is called "flexible work schedule." use a significance level of 0.10. what is the population parameter?