Class 9 Collection and Presentation of Data — practice questions with answers
Statistics and Probability · 5 sample questions from the school syllabus. Try each one, then open the answer and the worked solution.
1. What do we call a single fact or figure (numerical or otherwise) collected for a definite purpose?
AA datum
BA frequency
CA class
DA tally
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Answer: A) A datum
A single observation collected for a purpose is called a datum; the plural is data.
2. Which of these is NOT a way of presenting data?
ARandom guessing
BBar graph
CFrequency table
DHistogram
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Answer: A) Random guessing
Bar graphs, frequency tables and histograms all present data; random guessing is not a method of data presentation.
3. Which of these would normally be collected as primary data by a class teacher?
AHeights of her own students measured in class
BGDP of India from a yearbook
CRainfall data from a weather website
DPopulation from the census report
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Answer: A) Heights of her own students measured in class
Data the teacher measures herself for her purpose is primary; the others are taken from existing published sources (secondary).
4. A histogram of daily wages (in Rs) of workers is shown with classes of equal width 50. The tallest bar is over the class 200-250 with frequency 14. How many workers earn wages in the interval 200-250?
A15
B28
C14
D13
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Answer: C) 14
In a histogram with equal class widths, the bar height directly gives the frequency: 14 workers.
5. A continuous frequency distribution has class marks 17, 22, 27, 32, 37 and corresponding frequencies 3, 8, 12, 9, 8. Using the class width from the class marks, how many observations have a value of 24.5 or more?
A58
B32
C26
D29
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Answer: D) 29
Class size = 22 - 17 = 5, half = 2.5, so classes are 14.5-19.5, 19.5-24.5, 24.5-29.5, 29.5-34.5, 34.5-39.5. Values >= 24.5 lie in the last three classes: 12 + 9 + 8 = 29.