Mathematics (C1 & S1)

Question 1

Standard Deviation (Continuous)

Answer 1

√∑fx²/∑f - (mean)²

Question 2

Standard Deviation (Grouped)

Answer 2

√∑x²/n - (mean)²

Question 3

Use of Mathematical Models

Answer 3

• Quick and easy to produce
• Simplify a complex situation
• Improve our understanding of real world as certain variables can be changed
• Enable predications of the future
• Help provide control

Question 4

Disadvantages of Mathematical Models

Answer 4

• Only give a partial description of a real situation

- Only work for restricted range of values

Question 5

F(x)

Answer 5

P(X≤x)

Question 6

E(aX + b)

Answer 6

aE(X) + b

Question 7

Var(aX +b)

Answer 7

a² Var(X)

Question 8

What is a statistical model

Answer 8

A statistical process devised to describe or make predictions about the expected
behaviour of a real-world problem.

Question 9

Advantages of Quartiles

Answer 9

-Uses central 50% of the data
-Not affected by extreme values (outliers)
-Provide an alternative measure of spread to the
variance/standard deviation, i.e. IQR/STQR

Question 10

Disadvantages of Quartiles

Answer 10

-Not always a simple calculation, e.g. interpolation for a
grouped frequency distribution
-Different measures of calculation – no single argued method
-Does not use all the data directly