CBSE Class 9 Mathematics Frequency Distribution Assignment Set 02

Frequency Distribution - M.C.Q. Type

Choose the correct choice out of 4 choices.

Question 1. The data collected for the first time by a person is called,
(i) Raw data
(ii) Ungrouped data
(iii) Primary data
(iv) Secondary data
Answer: (iii) Primary data
Data collected by the investigator herself or himself with a specific objective in mind is called primary data.
In simple words: Primary data is firsthand information collected directly by the researcher.

Exam Tip: Remember that 'primary' implies original, firsthand collection for a fresh study.

Question 2. The collection of data, their analysis and interpretation is called,
(i) Raw data
(ii) Grouped data
(iii) Secondary data
(iv) Statistics
Answer: (iv) Statistics
Statistics is the branch of mathematics that deals with the collection, presentation, analysis, and interpretation of numerical data.
In simple words: Statistics is the science of learning from data.

Exam Tip: Learn the definition of statistics as it forms the fundamental base of this branch.

Question 3. The quantity that assumes different values is called,
(i) Variate
(ii) Tally bar
(iii) Frequency
(iv) Cumulative frequency
Answer: (i) Variate
A characteristic that can take on different values for different individuals or objects is called a variable or variate.
In simple words: A variate is a quantity that can change or take different values.

Exam Tip: Do not confuse variate with frequency, which is the count of occurrences.

Question 4. The class mark of 10-20 is
(i) 10
(ii) 20
(iii) 15
(iv) 5
Answer: (iii) 15
Class mark = \(\frac{\text{Lower limit} + \text{Upper limit}}{2}\)
Class mark = \(\frac{10 + 20}{2} = \frac{30}{2} = 15\)
In simple words: The class mark is the exact midpoint of a class interval.

Question 5. When the original data goes in the hand of a second person for interpretation, then this data is
(i) Raw data
(ii) Ungrouped data
(iii) Secondary data
(iv) None of the options
Answer: (iii) Secondary data
Data gathered from a source that has already been collected and compiled by someone else is known as secondary data.
In simple words: Secondary data is secondhand information obtained from someone else's records.

Exam Tip: Distinguish clearly between primary (self-collected) and secondary (third-party) data.

Question 6. The number of times a variate occurs is called
(i) Range
(ii) Class size
(iii) Frequency
(iv) Class-intervals
Answer: (iii) frequency
The number of times a particular observation appears in the given data is called its frequency.
In simple words: Frequency is simply the count of how many times a value repeats.

Exam Tip: Frequency counts repetitions in data tabulation.

Question 7. The difference between the maximum and minimum observation of a discrete series is
(i) Range
(ii) Class size
(iii) Class-interval
(iv) Limits
Answer: (i) Range
Range = Maximum value - Minimum value.
In simple words: Range measures how spread out the extreme values of data are.

Exam Tip: Range gives a quick measure of data dispersion.

Question 8. The class marks of a certain distribution are 47, 52, 57, 62, 67, 72. Its class size is
(i) 10
(ii) 5
(iii) 2.5
(iv) None of the options
Answer: (ii) 5
Class size is the difference between any two consecutive class marks.
Class size = \(52 - 47 = 5\)
In simple words: The distance between two neighboring class marks gives the class size.

Exam Tip: For evenly spaced class marks, the difference between any two consecutive marks equals the class width.

Question 9. A frequency distribution in which upper limit of a class is also included in that class. Such a class is called
(i) Inclusive class
(ii) Continuous class
(iii) Frequency class
(iv) Tally-bar class
Answer: (i) Inclusive class
In an inclusive method of classification, both lower and upper limits are included in that class interval.
In simple words: Inclusive classes include both their start and end boundary values.

Exam Tip: Inclusive classes have gaps between the upper limit of one class and the lower limit of the next.

Question 10. The difference between the lower limit of one class and the upper limit of the preceding class is
(i) adjustment factor
(ii) 2(adjustment factor)
(iii) \(\frac{1}{2}(\text{adjustment factor})\)
(iv) None of the options
Answer: (ii) 2(adjustment factor)
The gap between the upper limit of a class and the lower limit of the next class equals twice the adjustment factor used to convert inclusive classes into exclusive classes.
In simple words: The total gap between consecutive inclusive classes is twice the half-gap adjustment value.

Exam Tip: Adjustment factor is half of this gap, so the gap itself is twice the adjustment factor.