II PUC STATISTICS ONE MARK TWO MARKS QUESTIONS

1. State merits and demerits of moving average method.
Ans. Merits: a)it is simple to understand.
b)it is more flexible than any other methods.
Demerits: a) no trend values in the beginning and in the end.
b) choice of period of moving average is difficult.
2. Define Interpolation and extrapolation.
Ans. Interpolation is the technique of estimating the value of the depending variable
(y)for any intermediate value of the independent variable(x)
Extrapolation is the technique of estimating the value of the depending variable (y)
for any value of the independent variable(x) which is outside the range of the given
series.
3. What is discrete probability distribution and continuous probability distribution?
Ans: The probability distribution of a discrete random variable is known as discrete
probability distribution.
The probability distribution of a continuous random variable is known as continuous
probability distribution.
4. Define Bernoulli distribution.
Ans: A random variable X is said to follow Bernoulli distribution if its p.m.f is given by
P(x)=px q
1-x
,x=0,1.
5. Define Binomial distribution.
Ans: A random variable X is said to follow Bernoulli distribution if its p.m.f is given by
p(x)=ncx p
x
q
n-x
,x=0,1,….n.
6. Define Poisson distribution.
Ans: A random variable X is said to follow Poisson distribution if its p.m.f is given by
7. Define Hyper Geometric Distribution.
Ans: A random variable X is said to follow Hyper Geometric distribution if its p.m.f is
given by
8. Define Normal distribution.
Ans: A random variable X is said to follow Normal distribution if its p.d.f is given by
9. Mention the features of Bernoulli distribution.
Ans: a) the parameter is ‘p’
b) mean=p and variance=pq.
c) mean is greater than variance
10. Mention the features of Bernoulli distribution.
Ans: a) the parameters are ‘n’ and ‘p’.