Unit-8: Probability and statistics
(a) Basic concepts of probability and statistics
(b) Tabular and graphical representaion of data
(c) Measurement of central tendency
Q1.
Which is more reliable data primary data or secondary data.
(a) primary data (b) secondary data (c) both (d) none of these
Solution.
(a) primary data
Solution
Q2.
Mean of the data is 20, if each and every item of data is increased by 30, then the new mean of the data will be __________.
(a) 40 (b) 30 (c) 20 (d) 50
Solution.
(d) 50
Note : change of origin has impact on mean .
Solution
Q3.
Mean of a data is x, then the mean of y = 4x will be .
(a) 4x (b) 5x (c) x (d) x/2
Solution.
(a) 4x
Note : change of scale has impact on mean.
Solution
Q4.
Relation between mean, median and mode is
(a) Mode = 3Median (b) Mode = 2Mean + Median (c) Median = 2Mean + Mode
(d) Mode = 3Median - 2Mean
Solution.
(d) Mode = 3Median - 2Mean
Solution
Q5.
The mean of x and y is 8, and mean of x, y and z is 10, find the value of z.
(a) 18 (b) 14 (c) 20 (d) 16
Solution.
(x+y)/2 = 8
x + y = 16
(x + y + z)/3 = 10
x + y + z = 30
z= 14
Solution
Q6.
Find the mean of prime numbers between 20 and 30.
(a) 30 (b) 26 (c) 25 (d) 20
Solution.
Prime numbers = 23 and 29
=( 23 + 29)/2
= 52/2 = 26
Solution
Q7.
Probability of sure event is __________.
(a) 1 (b) 0 (c) 0.5 (d) none of these
Solution.
(a) 1
Solution
Q8.
Probability of occurrance of an event + Probability of non-occurrance of that event is
(a) 1 (b) 0 (c) 2 (d) none of these
Solution.
(a) 1
Solution
Q9.
If the probability of winning a game is 0.4, what is the probability of losing it ?
(a) 1 (b) 0.2 (c) 0.4 (d) 0.6
Solution.
(d) 0.6
P(winning) + P(losing) = 1
Solution
Q10.
Probability for impossible event will be _________.
(a) 0 (b) 1 (c) 0.2 (d) 0.5
Solution.
(a) 0
Solution
