Chapter 15 - Statistics

Exercise - 30

  1. The mean of 17osevatios is 20. If the mean of first 9 observations is 23 and that of last 9 observations is 18, find the 9th observation.
  2. The arithmetic mean of the following data is 11. Find the value of p.
    xi 5 8 11 14 17
    fi 2 4 8 p 2
  3. The arithmetic mean of the following data is 14. Find the value of k.
    xi
    5
    10
    15
    20
    25
    fi 7 k 8 4 5
  4. Find the value of p if mean of the following distribution is 7.5.
    x 3 5 7 9 11 13
    y 6 8 15 p 8 4
  5. The mean of the following frequency distribution is 57.6 and the sum of the observation is 50. Find the missing frequency f1 and f2.
    Class 0-20 20-40 40-60 60-80 80-100 100-120
    Frequency 7 f1 12 f2 8 5
  6. The following table gives the marks scored by 80 students in a class test:
    Marks 0-50 50-100 100-150 150-200 200-250 250-300
    Number of Students 8 12 20 25 10 5
    Find the mean marks scored by a student in the class-test.
  7. The following table gives the marks scored by 50 students in a class-test:

    Marks

    0-100

    100-200

    200-300

    300-400

    400-500

    500-600
    Number of Students

    2

    8

    12

    20

    5

    3
    Find the mean marks scored by a student in the class-test.
  8. The following table gives the marks scored by 100 students in a class-test:
    Marks 0-10 10-20 20-30 30-40 40-50 50-60
    Number of Students 12 18 27 20 17 6
    Find the mean marks scored by a student in the class-test.
  9. Find the mean of the following frequency distribution:
    Class interval 15-25 25-35 35-45 45-55 55-65
    Frequency 60 35 22 18 15
  10. Calculate the mean of the following frequency distribution:
    Class interval 10-20 20-30 30-40 40-50 50-60 60-70
    Frequency 11 15 20 30 14 10

  11. Calculate the Arithmetic mean of the following frequency distribution:
    Class interval 0-10 10-20 20-30 30-40 40-50 50-60 60-70
    Frequency 12 15 11 20 14 15 13
  12. Calculate the arithmetic mean of the following frequency distribution:
    Class interval 0-50 50-100 100-150 150-200 200-250 250-300
    Frequency 17 35 43 40 21 24

Answers

1. 27 2. 4 3. 6 4. 3
5. 8, 10 6. 145 7. 304 8. 28
9. 32.87 10. 40.1 11. 35.6 12. 148.61

 

Maths by Mr. M. P. Keshari
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Subjects Maths (Part-1) by Mr. M. P. Keshari
Chapter 9 Circle
Chapter 10 Tangents to a circle
Chapter 11 Geometrical Construction
Chapter 12 Troigonometry
Chapter 13 Height and Distance
Chapter 14 Mensuration
Chapter 15 Statistics
Chapter 16 Probability
Chapter 17 Co-ordinate Geometry