2.1 For a random sample of 12 married couples, the age difference (male age minus female age) in years is recorded below. For the above data calculate:

3

0

-4

7

12

2

4

-2

1

20

1

6

For this data calculate the:

2.1.1 mean (3)

2.1.2 range (2)

2.1.3 interquartile range (5)

2.1.4 mean deviation (5)

2.2 The average speed of a car over a certain distance is calculated by dividing the total distance travelled by the total time taken. Two towns A and B are 10 km apart, A motorist travels from A to B at an average speed of 20 km per hour, and travels from B to A at an average 40 km per hour.

2.2.1 Determine the average speed of the motorist for the two trips combined.(i.e from A to B and the back to A) (4)

2.2.2 What speed would the motorist have to average on the return trip from B to A to yield an overall speed of 30km per hour? (Assume the motorist has averaged 20km per hour from A to B) (6)