The following table shows the 300 employees of a glass manufacturing company, crossclassified

on the basis of age and department:

Age (years) Department

Production Sales Administration

< 30 60 25 18

30 - 50 70 29 25

> 50 30 8 35

An employee is selected at random from this company. Calculate the probability that the

employee is:

a) under 30 years of age?

b) a production worker?

c) a sales person and between 30 and 50 years of age?

d) over 50, given that he or she is in administration

question 2

The number of wooden chairs made per month by a backyard carpentry shop is a random

variable with the following probability distribution:

X 19 20 21 22

P(X = x) 0.4 0.25 0.2 0.15

a) What is the most probable number of chairs produced per month?

b) Find the probability that the number of chairs that will be made next month is at least 20.

c) Find the probability that the number of chairs produced per month is at most 21.

d) Find the expected number of chairs produced per month

question 3.

Jam is packed in tins of an average weight of 100g. The actual weight of jam delivered by the

filling machine is normally distributed about the set weight with a standard deviation of 2g.

Calculate the probability of tins of jam containing:

a) less than 98g

b) more than 103g

c) between 95g and 104g