Q2. If the mean of five observations x, x+2, x+4, x+6 and x+8 is 11, find the mean of first three observations.
(a) 11
(b) 9
(c) 15.5
(d) 11.2
Q3. If the mean of 6, 4, 7, p and 10 is 8, find the value of P.
(a) 17
(b) 14
(c) 13
(d) 12
Q4. If the heights of 5 persons are 114 cm, 152 cm, 151 cm, 158 cm and 155 cm, find the mean height.
(a) 170 cm
(b) 146 cm
(c) 160 cm
(d) 135 cm
Q5. The mode and mean are 26.6 and 28.1 respectively in an asymmetrical distribution. Find out the value of the median.
(a) 27.6
(b) 29.8
(c) 42.0
(d) 38.9
Q6. What is the range of 25, 12, 13, 5, 36, 10, 45, 50 ?
(a) 25
(b) 50
(c) 45
(d) 35
Q7. If the range of an ungrouped data is 51 and the highest value present in the data is 85, then the lowest value present in the data is
(a) 34
(b) 24
(c) 58
(d) 43
Q8. What is the class size of the class 29-92 ?
(a) 36
(b) 63
(c) 29
(d) 92
Q9. What is the class mark of the class 17-27 ?
(a) 10
(b) 22
(c) 44
(d) 54
Q10. What is the mode of 1, 2, 2, 2, 3, 3, 3, 3, 4, 4, 5, 5, 5, 6 ?
(a) 5
(b) 3
(c) 4
(d) 2
Solutions
S2. Ans.(b)
Sol. We have
11=(x+x+2+x+4+x+6+x+8)/5
⇒55=5x+20
⇒5x=35
⇒x=7
Now, the mean of first three observations:
=(x+x+2+x+4)/3=(3x+6)/3
=x+2=7+2=9
S3. Ans.(c)
Sol. Here, we have
8=(6+4+7+p+10)/5
⇒40=27+p
⇒p=40-27=13
S4. Ans.(b)
Sol. Mean height =(sum of heights of all persons)/(Number of persons)
=(114+152+151+158+155)/5
=730/5
=146 cm
S5. Ans.(a)
Sol. Mode = 3Median – 2Mean
Here, mode (Z) = 26.6, mean = 28.1
∴26.6=3Median-2×28.1
⇒3 Median = 26.6 + 56.2
⇒Median=82.8/3
⇒ Median = 27.6
S6. Ans.(c)
Sol. Arranging all the numbers in ascending order, we get
5, 10, 12, 13, 25, 36, 45, 50
Range = Highest value – Lowest valu
= 50 – 5 = 45
S7. Ans.(a)
Sol. Range = Highest value – Lowest value
Or, lowest value = Highest value – Range
= 85 – 51 = 34
S8. Ans.(b)
Sol. Class size = Upper limit – Lower limit
= 92 – 29
= 63
S9. Ans.(b)
Sol. We know that
classmark=(Upperlimit+Lowerlimit)/2
=(17+27)/2
= 22
S10. Ans.(b )
Sol. We know that the mode is the number that appears most often.
So here, the mode is 3.
