A sample of eight students were selected to test the effectiveness of a course designed to improve typing skills. Their typing scores before and after the course are recorded below. Test the course for effectiveness at α = 0.01. Student 1 2 3 4 5 6 7 8 Mean Std. dev. Before 45 38 60 35 70 48 39 49 48 11.88 After 56 42 62 39 75 50 42 56 52.75 12.13 Difference -11 -4 -2 -4 -5 -2 -3 -7 -4.75 3.012 What is the test statistic value?

The table below shows the approximate masses of a dust particle and a grain of pollen. dust particle 0.000000778 g grain of pollen 0.00000000155 g the mass of a dust particle can be estimated and written in the form a × 10^b, where a = 8 and b = the mass of a grain of pollen can be estimated and written in the form a × 10^b, where a = 2 and b = based on the estimates, the mass of a dust particle is approximately blank times larger than the mass of a grain of pollen.