X 0 1 2 3 4 y -2 -1 2 7 ? What is the missing term?
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Answer:
The mean of the combined group is 76.67 ≈ 77
Step-by-step explanation:
- The sum of the grades in Tom's group is 20×70 = 1400
- The sum of grades in Alice's group is 10×90=900
- The sum of gradees in the combined group is =1400+900=2300
- Then the mean grade of the combined group is
where
- 2300 is the sum of the all grades in the combined group
- 30 is the total number of people in the group