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CA Foundation · Quantitative Aptitude · Statistical Description of Data

The following table shows the less than cumulative frequencies of weekly overtime hours of 80 workers: less than 10: 8; less than 20: 26; less than 30: 55; less than 40: 74; less than 50: 80. What is the frequency of the class 30-40, and what is the percentage of workers with 20 or more hours of overtime?

The class 30-40 has frequency 19 and 67.5% of workers have 20 or more overtime hours. The frequency is 74 minus 55. Workers with at least 20 hours are 80 minus 26, which is 54, and 54 out of 80 equals 67.5 percent.

  1. A19 and 67.5%Correct
  2. B19 and 32.5%
  3. C29 and 67.5%
  4. D74 and 67.5%

Explanation

Frequency of 30-40 = 74 - 55 = 19. Workers with less than 20 hours = 26, so 20 or more = 80 - 26 = 54. Percentage = 54/80 x 100 = 67.5%. The 32.5% option is the share with under 20 hours (26/80), a wrong-side error. The 29 is the frequency of the class 20-30 (55 - 26).

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