Statistics Class 9
Question. The class mark of the class 90-130 is:
(a) 90
(b) 105
(c) 115
(d) 110
Answer: (d) 110
Question. The range of the data: 25, 81, 20, 22, 16, 6, 17,15,12, 30, 32, 10, 91, 8, 11, 20 is
(a) 10
(b) 75
(c) 85
(d) 26
Answer: (c) 85
Question. In a frequency distribution, the mid value of a class is 10 and the width of the class is 6. The upper limit of the class is:
(a) 6
(b) 7
(c) 10
(d) 13
Answer: (d) 13
Question. The width of each of five continuous classes in a frequency distribution is 5 and the lower class-limit of the lowest class is 10. The lower class-limit of the highest class is:
(a) 15
(b) 30
(c) 35
(d) 40
Answer: (b) 30
Question. Let m be the mid-point and 1 be the lower class limit of a class in a continuous frequency distribution. The upper class limit of the class is:
(a) 2m + l
(b) 2m – l
(c) m – l
(d) m – 2l
Answer: (b) 2m – l
Question. The class marks of a frequency distribution are given as follows:15, 20, 25, …The class corresponding to the class mark 15 is:
(a) 12.5 – 17.5
(b) 17.5 – 22.5
(c) 18.5 – 21.5
(d) 19.5 – 20.5
Answer: (a) 12.5 – 17.5
Question. In the class intervals 10-20, 20-30, the number 20 is included in:
(a) 10-20
(b) 20-30
(c) both the intervals
(d) none of these intervals
Answer: (b) 20-30
Question. A grouped frequency table with class intervals of equal sizes using 250-270 (270 not included in this interval) as one of the class interval is constructed for the following data:268, 220, 368, 258, 242, 310, 272, 342, 310, 290, 300, 320, 319, 304,402, 318, 406, 292, 354, 278, 210, 240, 330, 316, 406, 215, 258, 236.The frequency of the class 370-390 is:
(a) 0
(b) 1
(c) 3
(d) 5
Answer: (a) 0
Question. A grouped frequency distribution table with classes of equal sizes using 63-72 (72 included) as one of the class is constructed for the following data:30, 32, 45, 54, 74, 78, 108, 112, 66, 76, 88, 40, 14, 20, 15, 35, 44, 66, 75, 84, 95, 96, 102, 110, 88, 74, 112, 14, 34, 44. The number of classes in the distribution will be:
(a) 9
(b) 10
(c) 11
(d) 12
Answer: (b) 10
Question. To draw a histogram to represent the following frequency distribution:
the adjusted frequency for the class 25-45 is:
(a) 6
(b) 5
(c) 3
(d) 2
Answer: (d) 2
Question. The mean of five numbers is 30. If one number is excluded, their mean becomes 28. the excluded number is:
(a) 28
(b) 30
(c) 35
(d) 38
Answer: (d) 38
Question. If each observation of the data is increased by 5, then their mean
(a) remains the same
(b) becomes 5 times the original mean
(c) is decreased by 5
(d) is increased by 5
Answer: (d) is increased by 5
Question. The median of the data 78, 56, 22, 34, 45, 54, 39, 68, 54, 84 is
(a) 45
(b) 49.5
(c) 54
(d) 56
Answer: (c) 54
Question. For drawing a frequency polygon of a continues frequency distribution, we plot the points whose ordinates are the frequencies of the respective classes and abcissa are respectively:
(a) upper limits of the classes
(b) lower limits of the classes
(c) class marks of the classes
(d) upper limits of preceding classes
Answer: (c) class marks of the classes
Question. Mode of the data 15, 14, 19, 20, 16, 15, 16, 14, 15, 18, 14, 19, 16, 17, 16 is
(a) 14
(b) 15
(c) 16
(d) 17
Answer: (c) 16
Question. The mean of 25 observations is 26. Out of these observations if the mean of first 13 observations is 22 and that of the last 13 observations is 30, the 13th observation is:
(a) 23
(b) 26
(c) 28
(d) 30
Answer: (b) 26
Question. The ratio of the sum of observations and the total number of observations is called:
a. Mean
b. Median
c. Mode
d. Central tendency
Answer: a Mean
Question. The mean of x+2, x+3, x+4 and x-2 is:
a. (x+7)/4
b. (2x+7)/4
c. (3x+7)/4
d. (4x+7)/4
Answer: d (4x+7)/4
Explanation: Mean = (x+2+x+3+x+4+x-2)/4 = (4x+7)/4
Question. The median of the data: 4, 6, 8, 9, 11 is
a. 6
b. 8
c. 9
d. 11
Answer: b 8
Question. The median of the data: 155 160 145 149 150 147 152 144 148 is
a. 149
b. 150
c. 147
d. 144
Answer: a 149
Explanation: First arrange the data in ascending order. 144 145 147 148 149 150 152 155 160
Since, the number of observations here is odd, therefore,
Median = (n+1)/2 th = (9+1)/2 = 10/2 = 5th number = 149
Question. The median of the data: 17, 2, 7, 27, 15, 5, 14, 8, 10, 24, 48, 10, 8, 7, 18, 28 is:
a. 10
b. 24
c. 12
d. 8
Answer: c 12
Explanation: Arrange the given data in ascending order: 2, 5, 7, 7, 8, 8, 10, 10, 14, 15, 17, 18, 24, 27, 28, 48
Since, the number of observations given here is even,
hence, Median will be average of two middle terms.
n/2th = 16/2 = 8th term
(n/2 +1)th = (16/2 + 1)th = 9th term
Therefore,
Median = (10+14)/2 = 12
Question. The mode of the given data: 4, 6, 5, 9, 3, 2, 7, 7, 6, 5, 4, 9, 10, 10, 3, 4, 7, 6, 9, 9 is;
a. 7
b. 9
c. 10
d. 6
Answer: b 9
Explanation: First arrange the data in order:
2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 6, 7, 7, 7, 9, 9, 9, 9, 10, 10
Hence, mode = 9
Question. The value which appears very frequently in a data is called:
a. Mean
b. Median
c. Mode
d. Central tendency
Answer: c Mode
Question. The collection of information, collected for a purpose is called:
a. Mean
b. Median
c. Mode
d. Data
Answer: d Data
Question. The mean of the data 2, 3, 4, 5, 0, 1, 3, 3, 4, 3 is
a. 2
b. 2.2
c. 2.4
d. 2.8
Answer: d 2.8
Explanation: Mean = (2+3+4+5+0+1+3+3+4+3)/10 = 28/10 = 2.8
Question. Which of the following is not a measure of central tendency?
a. Standard deviation
b. Mean
c. Median
d. Mode
Answer: a Standard deviation
Question. Find the range of the following data: 25, 18, 20, 22, 16, 6, 17, 15, 12, 30, 32, 10, 19, 8, 11, 20.
a. 10
b. 15
c. 18
d. 26
Answer: d 26
Explanation: Range = Maximum value – Minimum value
Range = 32-6 = 26.
Question. What is the class mark of the class interval 90-120?
a. 90
b. 105
c. 115
d. 120
Answer: b 105
Explanation: Class mark = (upper limit + lower limit)/2
Class mark = (120+90)/2
Class mark = 105
Question. In the class intervals 10-20, 20-30, 20 is included in which interval?
a. 10-20
b. 20-30
c. Both the intervals
d. None of the intervals
Answer: b 20-30
Explanation: In the class intervals 10-20, 20-30, 20 is included in the interval 20-30, because the number is always included in the lower limit of the class interval.
Question. Find the class width for the grouped frequency distribution of the class intervals 1-20, 21-40, 41-60, ..
a. 10
b. 15
c. 17
d. 20
Answer: d 20
Explanation: Class width is the same as the class size. The class size of the given intervals 1-20, 21-40, 41-60,.. is 20.
Question. The arithmetic mean of the first 5 natural numbers is
a. 3
b. 4
c. 5
d. 6
Answer: a 3
Explanation: Arithmetic mean = (1+2+3+4+5)/5
Arithmetic mean = 15/5 = 3
Question. Find the value of x, if the arithmetic mean of 4, 5, 6, 7, 8 and x is 7.
a. 4
b. 6
c. 8
d. 12
Answer: d 12
Explanation: (4+5+6+7+8+x)/6 = 7
4+5+6+7+8+x = 7(6)
4+5+6+7+8+x = 42
30+x = 42
x = 42-30 = 12
Question. Find the mode of the following data: 15, 14, 19, 20, 14, 15, 16, 14, 15, 18, 14, 19, 15, 17, 15.
a. 14
b. 15
c. 16
d. 17
Answer: b 15
Explanation: The mode of the data 15, 14, 19, 20, 14, 15, 16, 14, 15, 18, 14, 19, 15, 17, 15 is 15, because the number 15 is repeated 5 times.
Question. If each data in the observation is increased by 5, then the mean
a. Remains the same
b. Increased by 5
c. Decreased by 5
d. None of the above
Answer: b Increased by 5
Explanation: If each data in the observation is increased by 5, then the mean is also increased by 5 because the mean is the average of the given values.
Question. The difference between the maximum and minimum values of the given observation is called
a. Class
b. Class interval
c. Class mark
d. Range
Answer: d Range
Explanation: The difference between the maximum and minimum values of the given observation is called range.
Question. Find the maximum value if the range is 38 and the minimum value is 82.
a. 60
b. 76
c. 120
d. 82
Answer: c 120
Explanation: We know that Range = Maximum value – Minimum value. Let the unknown value, (i.e) Maximum value be x.
Now, substitute the values,
38 = x – 82
x = 38+82
x = 120.
Therefore, the maximum value is 120.
Question. The number of times a particular items occur in a class interval called its:
a) Mean
b) Frequency
c) Cumulative frequency
d) Range
Answer: b) Frequency
Question. The mean wage of 150 labourers working in a factory running three shifts with 60, 40 and 50 labourers is Rs. 114. The mean wage of 60 labourers in the first shift is Rs.. 121.50 and that of 40 labourers working the second shift is Rs. 107.75, then the mean wage of those working in the third shift is:
a) Rs. 100
b) Rs. 110
c) Rs. 115.75
d) Rs. 120
Answer: b) Rs. 110
Question. Kavita obtained 16, 14, 18 and 20 marks (out of 25) in Maths in weekly tests in the month of Jan. 2000. The mean marks of Kavita is:
a) 16
b) 16.5
c) 17
d) 17.5
Answer: c) 17
Question. The range of the data: 25, 18, 20, 22, 16, 6, 17, 12, 30, 32, 10, 19, 8, 11, 20 is
a) 10
b) 15
c) 18
d) 26
Answer: d) 26
Question. The width of each five continuous classes in a frequency distribution is 5 and lower class-limit of the lowest class is 10. The upper class-limit of the highest class is:
a) 15
b) 25
c) 35
d) 40
Answer: c)35
Question. In the class interval 10 – 20, 20 – 30, the number 20 is included in:
a) 10 – 20
b) 20 – 30
c) Both the intervals
d) None of these intervals
Answer: b) 20 – 30
Question. A grouped frequency distribution table with classes of equal sizes using;63-72 (72 included) as one of the class is constructed for the following data:30, 32, 45, 54, 74, 78, 108, 112, 66, 76, 88,40, 14, 20, 15, 35, 44, 66, 75, 84, 95, 96, 102, 110, 88, 74, 112, 14, 34, 44
Question. The number of classes in the distribution will be:
a) 9
b) 10
c) 11
d) 12
Answer: c) 11
Question. To draw a histogram to represent the following frequency distribution:
| Class interval | 5-10 | 10-15 | 15-25 | 25-45 | 45-15 |
| Frequency | 6 | 12 | 10 | 8 | 15 |
the adjusted frequency for the class 25-45 is:
a) 6
b) 5
c) 3
d) 2
Answer: d) 2
Question. The mean of five numbers is 30. If one number is excluded, their mean becomes 28. The excluded number is:
a) 28
b) 30
c) 35
d) 38
Answer: d) 38
Question. If the mean of the observations:
x, x + 3, x + 5, x + 7, x + 10
is 9, the mean of the last three observations is:
Answer: c) 11
Question. There are 50 numbers. Each number is subtracted from 53 and the mean of the numbers so obtained is found to be –3.5. The mean of the given numbers is:
a) 46.5
b) 49.5
c) 53.5
d) 56.5
Answer: d) 56.5
Question. The mean factors of 24 is:
Answer: c)
Question. The range of the data 25.7, 16.3, 2.8, 21.7, 24.3, 22.7, 24.9 is:
a) 22
b) 22.9
c) 21.7
d) 20.5
Answer: b) 20.5
Question. If the class marks in a frequency distribution are 19.2, 26.5, 33.5, 40.5, then the class corresponding to the class mark 33.5 is:
a) 16-23
b) 23-30
c) 30-37
d) 37-41
Answer: c) 30-37
(a) 20 – 30
(b) 30 – 40
(c) 40 – 50
(d) 50 – 60
Question. Class mark of the 1st class interval is 5 and there are five classes. If the class size is 10 then the last class interval is
(a) 20 – 30
(b) 30 – 40
(c) 40 – 50
(d) 50 – 6 The median of the following data is
(a) 10
(b) 15
(c) 25
(d) 30
Question. The mode in the above frequency distribution table is
(a) 10
(b) 15
(c) 25
(d) 30
Question. The mean of the following data is
(a) 15
(b) 16
(c) 17
(d) none of these
Question. The median of first ten prime numbers is
(a) 11
(b) 12
(c) 13
(d) none of these.
Question. The mean of first ten multiples of 5 is
(a) 45
(b) 55
(c) 65
(d) none of these.
Question. The mean of first ten multiples of 2 is
(a) 11
(b) 12
(c) 13
(d) none of these.
Question. The median of first ten multiples of 3 is
(a) 15
(b) 16
(c) 16.5
(d) none of these.
Question. The median of the following data is
(a) 20
(b) 30
(c) 40
(d) none of these
Question. The median of the following data is 25 72 28 65 29 60 30 54 32 53 33 52 35 51 42 48 45 47 46 33
(a) 45
(b) 45.5
(c) 46
(d) none of these
Question. Calculate the median income from the following data:
(a) 20
(b) 30
(c) 40
(d) none of these
Question: The mean of 10 observation is 25. If one observation, namely 25, is deleted, the new mean is
a) 25
b) 28
c) 20
d) 22
Answer: 25
Question: Mean of the set of observations is the value which
a) is a representative of whole group
b) occurs most frequently
c) divides observations into two equal parts
d) is the sum of observations
Answer: is a representative of whole group
Question: If each entry of a data is increased by 5, then the arithmetic mean
a) increases by 5
b) none of the foregoing
c) remains the same
d) decreases by 5
Answer: d increases by 5
Question: The arithmetic mean of five given numbers is 85. Their sum is
a) 425
b) 85
c) more than 425
d) between 85 and 425
Answer: a 425
Question: The daily earnings (in rupees) of 10 workers in a factory are 8, 16, 19, 8, 16, 19, 16, 8, 19, 19. The median wage is
a) Rs. 16.00
b) Rs. 8.00
c) Rs. 17.50
d) Rs. 19.00
Answer: a Rs. 16.00
Question: The average weight of sample of 10 apples is 52 g. Later it was found that the weighing machine had shown the weight of each apple 10 g less. The correct average weight of an apple is
a) 62 g
b) 56 g
c) 54g
d) 52 g
Answer: a 62 g
Question: The mean of 6, y, 7, x and 14 is 8. Then
a) x + y = 13
b) 2x + 3y = 13
c) x – y = 13
d) None of these
Answer: a x + y = 13
Question: The mean of 994, 996, 998, 1000 and 1002 is
a) 998
b) 992
c) 1004
d) none
Answer: a 998
Question: The mode of a set of observations is the value which
a) occurs most frequently
b) is between maximum and minimum
c) is central
d) none of the foregoing
Answer: occurs most frequently
Question: The arithmetic mean for the following frequency distribution is
a) 26.5
b) 43.8
c) 42.3
d) 29.5
Answer: a 26.5
Question: The arithmetic mean of first five natural numbers is
a) 3
b) 5
c) 4
d) 6
Answer: a 3
Question: If the arithmetic mean of 6, 8, 5, 7, x and 4 is 7, then x is
a) 12
b) 8
c) 6
d) 4
Answer: a 12
Question: The arithmetic mean of first ten natural numbers is
a) 5.5
b) 7.5
c) 6
d) 10
Answer: a 5.5
Question: The weight (in kg) of 5 men are 62, 65, 69, 66 and 61. The median is
a) 65 kg
b) 45 kg
c) 55 kg
d) 66 kg
Answer: a 65 kg
Question. The minimum value o a data is 82 and range is 38, then the maximum value is
(a) 60
(b) 76
(c) 82
(d) 120
Answer: (d) 120
Question. In a grouped frequency distribution, the class intervals are 0-10, 10-20, 20-30, .., then the class width is
(a) 10
(b) 15
(c) 20
(d) 30
Answer: (a) 10Question. Which of the following variables are discrete?
- Size of shoes
- Number of pages in a book
- Distance travelled by a train
- Time
(a) 1 and 2
(b) 1 and 4
(c) 1 and 3
(d) 2 and 4
Answer: (a) 1 and 2
Question. Class mark of a class interval U-L is
(a) U+L2
(b) U-L2
(c) U-L
(d) 2(U+L)
Answer: (a) U+L2
Question. Which of the following is not a measure of central tendency?
(a) Standard deviation
(b) Mean
(c) Median
(d) Mode
Answer: (a) Standard deviation
Question. The mode of the given data: 4, 6, 5, 9, 3, 2, 7, 7, 6, 5, 4, 9, 10, 10, 3, 4, 7, 6, 9, 9 is;
(a) 7
(b) 9
(c) 10
(d) 6
Answer: (b) 9
Question. Given the class intervals 1-10, 11-20, 21-30, ___, then 20 is considered in class
(a) 11-30
(b) 11-20
(c) 21-30
(d) 15-25
Answer: (b) 11-20
Question. A student collects information about the number of school going children in a locality consisting of a hundred households. The data collected by him is
(a) Arrayed data
(b) Primary data
(c) Secondary data
(d) Grouped data
Answer: (b) Primary data
Question. One of the sides of a frequency polygon is
(a) either of the coordinate axes
(b) the x-axis
(c) neither of the coordinate axes
(d) the y-axis
Answer: (b) the x-axis
Question. In order to draw a frequency polygon by using a histogram, which of the following statements is incorrect?
(a) Obtain the mid-points of three class- intervals of highest frequency on Y-axis, one adjacent to the first on its right and one adjacent to the last, on its left.
(b) Obtain the frequency distribution and draw a histogram representing it.
(c) Join these mid-points of the adjacent rectangles of the histogram by dotted line
(d) Obtain the mid points of the upper horizontal side of each rectangle.
Answer: (a) Obtain the mid-points of three class- intervals of highest frequency on Y-axis, one adjacent to the first on its right and one adjacent to the last, on its left.
Question. The mean of five observations is 15. If the mean of first three observations is 14 and that of last three is 17, then the third observation is
(a) 29
(b) 31
(c) 32
(d) 18
Answer: (d) 18
Question. Mode of a set of observations is the value which
(a) is the sum of the observations
(b) occurs most frequently
(c) is the mean of the middle two observations
(d) divides the observations into two equal parts
Answer: (b) occurs most frequently
Question. The mean for counting numbers through 100 is
(a) 47.5
(b) 51
(c) 50.5
(d) 49.5
Answer: (c) 50.5
Question. The maximum frequency 10 is for the observation 4. Hence the mode of the data is
(a) 2
(b) 10
(c) 3
(d) 4
Answer: (d) 4
Question. Mohan has marks of 92, 85, and 78 in three mathematics tests. In order to have an average of exactly 87 for the four math tests, he should obtain
(a) 93 marks
(b) 90 marks
(c) 92 marks
(d) 91 marks
Answer: (a) 93 marks
Question. In an examination, ten students scored the following marks: 60, 58, 90, 51, 47, 81, 70, 95, 87, 99. The range of this data is
(a) 60
(b) 51
(c) 61
(d) 52
Answer: (d) 52
Question. In a grouped frequency distribution, the class intervals are 1-20, 21-40, 41-60, . . , then the class width is
(a) 10
(b) 10.5
(c) 15
(d) 20
Answer: (d) 20
Question. The range of the data 20, 8, 20, 18, 16, 15, 30, 12, 22, 6, 11, 17, 25, 32, 10, 19 is
(a) 15
(b) 16
(c) 18
(d) 26
Answer: (d) 26
Question. The consecutive class marks of a data having continuous class intervals having class width as 5, have a gap of ________ between them.
(a) 2.5
(b) 4.5
(c) 5
(d) 10
Answer: (c) 5
Question. In an examination, ten students scored the following marks: 60, 58, 90, 51, 47, 81, 70, 95, 87, 99. The range of this data is
(a) 52
(b) 51
(c) 81
(d) 60
Answer: (a) 52
Question. Class size for the following distribution: 0 – 0.25, 0.25 – 0.50, 0.50 – 0.75 is
(a) 10
(b) 0. 25
(c) 50
(d) 2.5
Answer: (b) 0. 25
Question. For a given data, the difference between the maximum and minimum observation is known as its
(a) class
(b) class mark
(c) range
(d) class limit
Answer: (c) range
Question. Which of the following variables are discrete ? 1. Size of shoes, 2. Number of pages in a book, 3. Distance travelled by a train, 4. Time
(a) 1 and 2
(b) 1 and 4
(c) 1 and 3
(d) 2 and 4
Answer: (a) 1 and 2
Question. In order to draw a frequency polygon by using a histogram, which of the following statements is incorrect?
(a) Obtain the mid-points of three class- intervals of highest frequency on Y-axis, one adjacent to the first on its right and one adjacent to the last, on its left.
(b) Obtain the frequency distribution and draw a histogram representing it.
(c) Join these mid-points of the adjacent rectangles of the histogram by dotted line
(d) Obtain the mid points of the upper horizontal side of each rectangle.
Answer:(a) Obtain the mid-points of three class- intervals of highest frequency on Y-axis, one adjacent to the first on its right and one adjacent to the last, on its left.
Question. To analysis the election results, the data is collected from a newspapers. The data thus collected is known as
(a) secondary data
(b) raw data
(c) grouped data
(d) primary data
Answer: (a) secondary data
Question. A graphical representation of a frequency distribution in the form of rectangles with class interval as bases and heights proportional to corresponding frequencies such that there is no gap between any two successive rectangles is called a
(a) Frequency polygon
(b) Histogram
(c) Bar graph
(d) Pie chart
Answer: (b) Histogram
Question. A student collects information about the number of school going children in a locality consisting of a hundred households. The data collected by him is
(a) Arrayed data
(b) Grouped data
(c) Primary data
(d) Secondary data
Answer: (c) Primary data
Question. In a frequency distribution, the class-width is 4 and the lower limit of first class is 10. If there are six classes, the upper limit of last class is
(a) 32
(b) 34
(c) 26
(d) 30
Answer: (b) 34
Question. Class mark of a class interval U-L is
(a) U+L/2
(b) U-L/2
(c) U-L
(d) 2(U+L)
Answer: (a) U+L/2
Question. The class size of a distribution is 25 and the first class interval is 200-224. Then, the class marks of first two class intervals are
(a) 237, 287
(b) 212, 237
(c) 237, 262
(d) 212, 262
Answer: (b) 212, 237
Question. In a grouped frequency distribution, the class intervals are 0-10, 10-20, 20-30, .., then the class width is
(a) 10
(b) 15
(c) 20
(d) 30
Answer: (a) 10
Question. The mean of first four prime numbers is
(a) 4
(b) 4.5
(c) 3.75
(d) 4.25
Answer: (d) 4.25
Question. The mean for counting numbers through 100 is
(a) 47.5
(b) 51
(c) 50.5
(d) 49.5
Answer: (c) 50.5
The following tables shows the age distribution of case admitted during a day in two different hospitals
Table 1
| Age (in years) | 5-15 | 15-25 | 25-35 | 35-45 | 45-55 | 55-65 |
| No. of cases | 6 | 11 | 21 | 23 | 14 | 5 |
Table 2
| Age (in years) | 5-15 | 15-25 | 25-35 | 35-45 | 45-55 | 55-65 |
| No. of cases | 8 | 16 | 10 | 42 | 24 | 12 |
Refer to table 1
Question. The average age for which maximum cases occurred is
a) 32.24
b) 34.36
c) 36.82
d) 42.24
Answer: c) 36.82
Question. The upper limit of modal class is
a) 15
b) 25
c) 35
d) 45
Answer: d) 45
Question. The mean of the given data is
a) 26.2
b) 32.4
c) 33.5
d) 35.4
Answer: d) 35.4
Refer to table 2
Question. The mode of the given data is
a) 41.4
b) 48.2
c) 55.3
d) 64.6
Answer: a) 41.4
Question. The median of the given data is
a) 32.7
b) 40.2
c) 42.3
d) 48.6
Answer: b) 40.2
Electricity Energy Consumption
CASE STUDY 2:
Electricity energy consumption is the form of energy consumption that uses electric energy. Global electricity consumption continues to increase faster than world population, leading to an increase in the average amount of electricity consumed per person (per capita electricity consumption).
A survey is conducted for 56 families of a Colony A. The following tables gives the weekly consumption of electricity of these families.
| Weekly consumption (in units) | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
| No. of families | 16 | 12 | 18 | 6 | 4 | 0 |
The similar survey is conducted for 80 families of Colony B and the data is recorded as below:
| Weekly consumption (in units) | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
| No. of families | 0 | 5 | 10 | 20 | 40 | 5 |
Refer to data received from Colony A
Question. The median weekly consumption is
a) 12 units
b) 16 units
c) 20 units
d) None of these
Answer: c) 20 units
Question. The mean weekly consumption is
a) 19.64 units
b) 22.5 units
c) 26 units
d) None of these
Answer: a) 19.64 units
Question. The modal class of the above data is I
a) 0-10
b) 10-20
c) 20-30
d) 30-40
Answer: c) 20-30
Refer to data received from Colony B
Question. The modal weekly consumption is
a) 38.2 units
b) 43.6 units
c) 26 units
d) 32 units
Answer: b) 43.6 units
5. The mean weekly consumption is
a) 15.65 units
b) 32.8 units
c) 38.75 units
d) 48 units
Answer: c) 38.75 units
Question. In a frequency distribution, ogives are graphical representation of
(a) Frequency
(b) Relative frequency
(c) Cumulative frequency
(d) Raw data
Solution
(c) Cumulative frequency
In a frequency distribution, ogives are graphical representation of cumulative frequency.
Hence, the correct answer is option (c).
Question. A frequency polygon is constructed by plotting frequency of the class interval and the
(a) Upper limit of the class
(b) Lower limit of the class
(c) Mid value of the class
(d) Any values of the class
Solution
(c) mid value of the class
Frequency polygon is the plot of frequencies vs. the mid values of the classes.
Hence, the correct answer is option (c)
Question. In a histogram the area of each rectangle is proportional to
(a) the class mark of the corresponding class interval
(b) the class size of the corresponding class interval
(c) frequency of the corresponding class interval
(d) cumulative frequency of the corresponding class interval
Solution
(c) frequency of the corresponding class interval
In a histogram the area of each rectangle is proportional to the frequency of the corresponding class interval.
Hence, the correct answer is option (c).
Question. In the ‘less than’ type of ogive the cumulative frequency is plotted against
(a) the lower limit of the concerned class interval
(b) the upper limit of the concerned class interval
(c) the mid-value of the concerned class interval
(d) any value of the concerned class interval
Solution
(b) the upper limit of the concerned class interval
In the less than type of ogive the cumulative frequency is plotted against the upper limit of the concerned class interval.
Hence, the correct answer is option (b).
Question. In a histogram the class intervals or the group are taken along
(a) Y-axis
(b) X-axis
(c) both of X-axis and Y-axis
(d) in between X and Y axis
Solution
(b) X-axis
In a histogram the class intervals or the groups are taken along the horizontal axis or X-axis.
Hence, the correct answer is option (b).
Question. A histogram is a pictorial representation of the grouped data in which class intervals and frequency are respectively taken along
(a) vertical axis and horizontal axis
(b) vertical axis only
(c) horizontal axis only
(d) Horizontal axis and vertical axis
Solution
(d) Horizontal axis and vertical axis
In a histogram the class intervals and frequencies are taken along horizontal and vertical axes respectively.
Hence, the correct option is (d).
Question. In a histogram, each class rectangle is constructed with base as
(a) Frequency
(b) Class-intervals
(c) Range
(d) Size of the class
Solution
(b) Class-intervals
In a histogram, the class rectangles are constructed with base as the class-intervals.
Hence, the correct answer is option (b).