Introduction to Data Interpretation
Direction: Study the histogram of marks (in Mathematics) distribution of 50 students of class IX and answer the following questions.

- The average marks of the students are
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On the basis of given graph in question , we have
Here , f1 = 10 , x1 = 7 , f2 = 30 , x2 = 8 , f3 = 50 , x3 = 18 , f4 = 70 , x4 = 4 , f5 = 90 , x5 = 13Mid-value of class-interval (x) = Highest value + Lowest value 2 ∴ Average = Σ fx Σ f
where Σf = Total number of studentsRequired average marks = 10 × 7 + 30 × 8 + 50 × 18 + 70 × 4 + 90 × 13 50
Correct Option: A
On the basis of given graph in question , we have
Here , f1 = 10 , x1 = 7 , f2 = 30 , x2 = 8 , f3 = 50 , x3 = 18 , f4 = 70 , x4 = 4 , f5 = 90 , x5 = 13Mid-value of class-interval (x) = Highest value + Lowest value 2 ∴ Average = Σ fx Σ f
where Σf = Total number of studentsRequired average marks = 10 × 7 + 30 × 8 + 50 × 18 + 70 × 4 + 90 × 13 50 Required average marks = 70 + 240 + 900 + 280 + 1170 50 Required average marks = 2660 = 53.2 50
- The number of students who have secured marks less than 60 is :
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From the given above histogram , we can see
The number of students who have scored interval 0-20 = 7
The number of students who have scored interval 0-20 = 8
The number of students who have scored interval 0-20 = 18Correct Option: C
From the given above histogram , we can see
The number of students who have scored interval 0-20 = 7
The number of students who have scored interval 0-20 = 8
The number of students who have scored interval 0-20 = 18
Students who score less than 60 marks = 7 + 8 + 18 = 33
Direction: Study the following histogram of data related to literate people of different age groups and answer the questions given below.

- The respective ratio of literate people in the age group of 20 to 35 years to that in the age group of 30 to 45 years is
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According to given histogram , we have
Number of literate people in the age group of 20 to 35 years = 800 + 650 + 600 = 2050
Number of literate people in the age group of 30 to 45 years = 600 + 500 + 250 = 1350
Required ratio = Number of literate people in the age group of 20 to 35 years : Number of literate people in the age group of 30 to 45 yearsCorrect Option: C
According to given histogram , we have
Number of literate people in the age group of 20 to 35 years = 800 + 650 + 600 = 2050
Number of literate people in the age group of 30 to 45 years = 600 + 500 + 250 = 1350
Required ratio = Number of literate people in the age group of 20 to 35 years : Number of literate people in the age group of 30 to 45 years
∴ Required ratio = 2050 : 1350 = 41 : 27
- The percentage of the literate people in the age group 30 to 45 years is
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On the basis of given graph in question ,
Number of literate people in the age group 30–45 years = 600 + 500 + 250 = 1350
Total literate people = 3700 + 350 = 4050Required percent = 1350 × 100 4050
Correct Option: B
On the basis of given graph in question ,
Number of literate people in the age group 30–45 years = 600 + 500 + 250 = 1350
Total literate people = 3700 + 350 = 4050Required percent = 1350 × 100 4050 Required percent = 100 = 33.33% 3
- The number of literate people in the age group of 20 to 35 years is
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According to given histogram , we have
Number of literate people in the age interval 20-25 = 800
Number of literate people in the age interval 25-30 = 650
Number of literate people in the age interval 30-35 = 600Correct Option: A
According to given histogram , we have
Number of literate people in the age interval 20-25 = 800
Number of literate people in the age interval 25-30 = 650
Number of literate people in the age interval 30-35 = 600
Required answer = 800 + 650 + 600 = 2050