A research organization is studying the average time that individuals in two different departments of a large corp spend on work related tasks each day suppose that for a simple random sample of 45 employees in department x, the mean time spent is 7.5 hours a day with a standard deviation of 1.8 hours. In an independent simple random sample of 50 employees in department y, the mean time spent is 6.2 hours a day with a standard deviation of 2.0 hours. What is the point estimate of the difference between the mean number of hours that dept x employees spend on work related tasks per day and the mean number of hours that dept y employees spend on work related tasks per day