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Question 24

One group of 3 numbers has a mean of 10, and a second group of 2 numbers has a mean of 5. Which statements about the mean of all 5 numbers are true? Select all that apply.

  1. The mean of all 5 numbers is 7.5, the average of 10 and 5.
  2. The mean of all 5 numbers is 40.
  3. The first group totals 30 and the second totals 10.Correct answer
  4. The two group means can be averaged directly because both groups are small.
  5. The mean of all 5 numbers is 8.Correct answer

Explanation

The groups total 3 lots of 10, which is 30, and 2 lots of 5, which is 10, so all five numbers total 40 and their mean is 40 divided by 5. Averaging the two group means gives 7.5 and would only be right if the groups were the same size, because the larger group of three pulls the combined figure closer to 10.

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Question 24: One group of 3 numbers has a mean of 10, and a second group… · Statistics and Probability · Questena