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A distribution of scores has a mean of µ = 50. One new score is added to the distribution and the new mean is found to be µ = 48. From this result, you can conclude that the new score was ____.​Group of answer choices​less than 50​greater than 50​equal to 48​between 50 and 52

Question

A distribution of scores has a mean of µ = 50. One new score is added to the distribution and the new mean is found to be µ = 48. From this result, you can conclude that the new score was ____.​Group of answer choices​less than 50​greater than 50​equal to 48​between 50 and 52

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Solution

To determine the new score added to the distribution, we can use the information given about the means before and after the new score was added.

  1. Let N N be the number of scores in the original distribution.
  2. The original mean is μ=50 \mu = 50 , so the total sum of the original scores is 50N 50N .
  3. After adding one new score X X , the new mean becomes μ=48 \mu = 48 .
  4. The new total number of scores is N+1 N + 1 .
  5. The new total sum of the scores is 50N+X 50N + X .

Using the formula for the mean: New mean=New total sumNew total number of scores \text{New mean} = \frac{\text{New total sum}}{\text{New total number of scores}}

Substitute the given values: 48=50N+XN+1 48 = \frac{50N + X}{N + 1}

To find X X , solve the equation step by step:

  1. Multiply both sides by N+1 N + 1 : 48(N+1)=50N+X 48(N + 1) = 50N + X

  2. Distribute 48 on the left side: 48N+48=50N+X 48N + 48 = 50N + X

  3. Subtract 48N 48N from both sides: 48=2N+X 48 = 2N + X

  4. Isolate X X : X=482N X = 48 - 2N

Since N N is a positive integer, 2N 2N is a positive number. Therefore, 482N 48 - 2N will be less than 48.

Thus, the new score X X was less than 48.

This problem has been solved

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