What is the mean of the distribution?

Consider the following data for the next two (02) items that follow :<br><table> <thead><tr><th>Class</th><th>40–50</th><th>50–60</th><th>60–70</th><th>70–80</th></tr></thead> <tbody> <tr><td>Frequency</td><td>4</td><td>3</td><td>1</td><td>2</td></tr> </tbody> </table>

  1. A. 51
  2. B. 52
  3. C. 54
  4. D. 56

Correct Answer: D. 56

Explanation

Class marks (x_i) are 45, 55, 65, 75. Sum of f_i x_i = (4 \times 45) + (3 \times 55) + (1 \times 65) + (2 \times 75) = 180 + 165 + 65 + 150 = 560. Total frequency N=10. Mean = \frac{560}{10} = 56.

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