Statistics quiz

The class mark of the class 90-120 is:

The class size of the class 10-25 is:

In a histogram, the rectangles are:

A frequency polygon is obtained by joining the:

In a bar graph, the widths of the bars are:

If the class marks are 10, 15, 20, 25, the class size is:

In a histogram with unequal class widths, the heights of rectangles must be:

The lower limit of the class 25-35 is:

The number of times an observation occurs is called its:

To close a frequency polygon, we take classes at each end with frequency:

Find the class marks of 0-5, 5-10 and 10-15. (2 marks)

Convert the classes 10-19, 20-29 and 30-39 into continuous classes. (2 marks)

Why do we use a kink or zig-zag on the horizontal axis of a histogram? (2 marks)

The class mark of a class is 25 and the class size is 10. Find the class limits. (2 marks)

What is the difference between primary and secondary data? (2 marks)

Why is the area of each rectangle in a histogram important? (2 marks)

Give two situations where a bar graph is better than a histogram. (2 marks)

What is the range of the data 12, 45, 23, 67, 34, 8? (2 marks)

How can you draw a frequency polygon without a histogram? (2 marks)

Why are the classes 0-10, 10-20 called continuous or overlapping? Where does 10 go? (2 marks)

Classes 0-5, 5-10, 10-20, 20-30 and 30-50 have frequencies 10, 15, 20, 12 and 8. Find the adjusted frequency of each class taking the minimum class size as 5. (3 marks)

The weights in kg of 15 students are: 38, 42, 45, 39, 51, 47, 44, 40, 52, 36, 48, 43, 46, 41, 50. Make a frequency table with classes 35-40, 40-45, 45-50 and 50-55. (3 marks)

In a frequency distribution, the class marks are 22, 30, 38, 46 and 54. Find the class size and the five class intervals. (3 marks)

In a survey of 200 families, the numbers having 0, 1, 2, 3 and 4 children are 10, 50, 90, 40 and 10. Find the percentage of families having 2 children and having at most 1 child. (3 marks)

The heights of rectangles in a histogram with class width 10 are 4, 9, 14, 8 and 5. Find the total number of observations. If one class of width 20 has frequency 18, what height should its rectangle have, using 10 as the base width? (3 marks)

Read the passage and answer the questions. A school recorded the number of books read by students in a month: 0-2: 12, 2-4: 25, 4-6: 18, 6-8: 10, 8-10: 5. (i) How many students were surveyed? (ii) Which class has the highest frequency? (iii) What type of graph is best to show this data, and why? (5 marks)

Read the passage and answer the questions. A hospital records the ages of 50 patients: 0-10: 5, 10-20: 8, 20-30: 12, 30-40: 15, 40-50: 10. (i) Find the class mark of each class. (ii) Which age group has the most patients? (iii) Explain how to draw a frequency polygon for this data. (5 marks)

Read the passage and answer the questions. A survey records the time taken by 40 students to reach school: 0-10 min: 8, 10-20 min: 14, 20-40 min: 12, 40-60 min: 6. (i) Why are the class widths unequal? (ii) Find the adjusted frequencies using the minimum class size. (iii) Which class has the tallest rectangle? (5 marks)

Read the passage and answer the questions. The production of wheat in a state over five years was: 2021: 30 lakh tonnes, 2022: 34, 2023: 28, 2024: 38, 2025: 40. (i) Which graph should be used to show this data? (ii) In which year was production lowest? (iii) Find the percentage increase from 2023 to 2025, correct to one decimal place. (5 marks)

Read the passage and answer the questions. The daily earnings of 30 vendors are: 100-200: 4, 200-300: 9, 300-400: 10, 400-500: 5, 500-600: 2. (i) How many vendors earn Rs 300 or more? (ii) Find the class mark of the modal class. (iii) What percentage earn less than Rs 200, correct to one decimal place? (5 marks)

Draw a histogram and a frequency polygon on the same graph for the marks of 50 students: 0-10: 5, 10-20: 10, 20-30: 15, 30-40: 12, 40-50: 8. (6 marks)

Draw a bar graph for the following literacy rates of five states: P 82%, Q 75%, R 94%, S 68%, T 88%. Write three conclusions from the graph. (6 marks)

Draw a histogram for the following data with unequal classes: 10-20: 6, 20-25: 8, 25-30: 10, 30-40: 12, 40-60: 8. Show how adjusted frequencies are found. (6 marks)

The following are the runs scored by two batsmen in 10 innings each: P: 32, 45, 12, 60, 48, 35, 50, 20, 38, 42; Q: 15, 70, 5, 80, 25, 10, 65, 30, 55, 20. Make frequency tables with classes 0-20, 20-40, 40-60, 60-80, 80-100 and draw frequency polygons for both on the same graph. Who is more consistent? (6 marks)

A class of 40 students records hours spent watching television per week: 0-5: 6, 5-10: 10, 10-15: 12, 15-20: 8, 20-25: 4. Draw a histogram and a frequency polygon, and write three observations from the graphs. (6 marks)