Question

Use the following dot plot to answer the questions.

What is the mean of the set?

If an additional dot is added to the set in the 3 column, how will the mean change? What will the new mean be?

Answer 1

3.4

Decrease ; 3.375

Explanation:

Mean = Σfx / Σf

Σfx = (1 * 2) + (2 * 2) + (3 * 3) + (4 * 9) = 51

Σf = 1 + 2 + 3 + 9 = 15

Mean = 51 / 15 = 3.4

If 1 more dot is added to the 3rd column:

Σfx = (1 * 2) + (2 * 2) + (3 * 4) + (4 * 9) = 54

Σf = 1 + 2 + 4 + 9 = 16

Mean = 54 / 16 = 3.375