In preparing for a test on a set of material, is it better to study one topic at a time or to study topics mixed together? in one study,1 a sample of fourth graders were taught four equations. half of the children learned by studying repeated examples of one equation at a time, while the other half studied mixed problem sets that included examples of all four types of calculations grouped together. a day later, all the students were given a test on the material. the students in the mixed practice group had an average grade of 77, while the students in the one-at-a-time group had an average grade of 38. what is the best estimate for the difference in the average grade between fourth-grade students who study mixed problems and those who study each equation independently?

I've been working on this for a few days and i just don't understand, it's due in a few hours. you.the direction of a vector is defined as the angle of the vector in relation to a horizontal line. as a standard, this angle is measured counterclockwise from the positive x-axis. the direction or angle of v in the diagram is α.part a: how can you use trigonometric ratios to calculate the direction α of a general vector v = < x, y> similar to the diagram? part bsuppose that vector v lies in quadrant ii, quadrant iii, or quadrant iv. how can you use trigonometric ratios to calculate the direction (i.e., angle) of the vector in each of these quadrants with respect to the positive x-axis? the angle between the vector and the positive x-axis will be greater than 90 degrees in each case.part cnow try a numerical problem. what is the direction of the vector w = < -1, 6 > ?