In: Statistics and Probability
Read four digits from the random numbers table. note the number of odd digits in the selected numbers. Repeat the experiment 25 times. Obtain the probability distribution of the odd digits. Find mean and variance of the distribution
Ans. The toatal number of possible for digit numbers are
The odd numbers = 105
The even numbers = 105
Ley,
Yi = 1 if number is odd = success
= 0 if number is even = failure
p = (Yi = 1) = P( odd number) = 105/210 = 0.5
q = 1 - p = 0.5
Such types of experiment is known as bernoulBe trial.
Since this trial is repeated n = 25 times, each trail is independentl from each other and with constant probability p = 0.5 of success for each trail.
Let X = Y1 + Y2 + ....+ Y25 has binomial distribution with parameters n = 25 and p = 0.5.
Mean = E(X) = np = 25*0.5 = 12.5
Variance= var(X) = npq = 25*0.5*0.5 = 6.25