3.26 Mix It Up for Better Learning In preparing for a test on a set of material, is it better to study one topic at a time or to stud}.F topics mixed together? In one studjtgl?" 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 dayr later, all the students were given a test on the material. The students in the mixed practice group had an average grade of ?T, while the students in the oueatatime group had an average grade of 38. What is the best estimate for the difference in the average grade between fourthgrade students who study mixed problems and those who studyr each equation independently? Give notation [as a difference with a minus sign) for the quantity we are trying to estimate, notatiou for the truantitj,r that gives the best estimate, and the value of the best estimate. Be sure to clearly define an}? parameters in the context of this situation