INTERNATIONAL UNIVERSITY OF BUSINESS AGRICULTURE AND TECHNOLOGY

Quiz examination

STA 240 Set: Z

Full marks: 100 Time: 50 minutes

1. Write down the applications of Poisson distribution and properties of normal distribution.

2. What is random variable? Explain with an example.

3. The number of persons X, in a family chosen at random has the following probability distribution:

X 1 2 3 4 5 P(X) 0.1 0.2 m 0.1 0.2

A) Find the value of m.

B) Find the average family size E (X).

C) Also find V(X).

4. p(x)=7x10 ; 1<x<2

A) Find E (X).

B) Also find V(X).

5. Hospital records show that of patients suffering from a certain disease, 25% die of it.

What is the probability that of 10 randomly selected patients, 5 will recover?

6. A company makes electric motors. The probability an electric motor is defective is 0.05.

What is the probability that a sample of 500 electric motors will contain exactly 10

defective motors?

7. Find the following probabilities:

(a) P (Z > 1.06)

(b) (c) P (1.01 < Z < 2.04)

Md. Mortuza Ahmmed