Which of the given is an example of a matched pairs design? Group of answer choices A teacher compares the pre‑test and post‑tes
t scores of students. A teacher compares the scores of students who had a computer‑based method of instruction with the scores of other students who had a traditional method of instruction. A teacher compares the scores of students in her class on a standardized test with the national average score. A teacher calculates the average of students' scores on a pair of tests and wishes to see if this average is larger than 80%.
Answer:So you need to calculate a weighted average, where the average of 70 has twice the weight of the average of 85 (20 students vs 10). The easiest way to think about it is to split the 20 into two groups of 10 so that you have three groups of 10 students, that way you can just average the scores as normal.
So, you have three averages of 85, 75 and 75.
Total average = (85+75+75)/3 = 78.33... hopes this helps
