# Maths revsion

handling data

- Created by: Georgina Bene
- Created on: 05-04-13 13:40

## Slides in this set

### Slide 1

### Slide 2

Higher Tier Handling Data revision

Contents : Questionnaires

Sampling

Scatter diagrams

Pie charts

Frequency polygons

Histograms

Averages

Moving averages

Mean from frequency table

Estimating the mean

Cumulative frequency curves

Box and whisker plots

Theoretical probability

Experimental probability

Probability tree diagrams…read more

### Slide 3

Be careful when deciding what questions to

Questionnaires ask in a survey or questionnaire

What is your age? Don't be personal

Burning fossil fuels is Don't be leading

dangerous for the earth's

Do you

future, buy you

don't lemonade

agree?when Don't reduce the number

youyou

Do arenever

at Tescos?

eat non- of people who can answer

polysaturate margarines or the question

not? Yes or no? Don't be complicated

Here is an alternative set of well constructed questions. They

require yes/no or tick-box answers.

How old are you? 0-20, 21-30, 31-40, 41-50, 0ver 50

Do you agree with burning fossil fuels?

Do you like lemonade?

Which margarine do you eat?

Flora, Stork, Other brand, Don't eat margarine

This last question is very good since all of the possible answers

are covered. Always design your questionnaire to get the data you want.…read more

### Slide 4

When it is impossible to ask a whole population to take

SamplingThepart in a survey or a questionnaire, you have to sample

larger

a smaller part of the population.

the Therefore the sample has to be representative of

samplethe population and not be biased.

the

RANDOM SAMPLING

Here every better

member of a population has an equal chance of being chosen:

Names out of a bag, random numbers on a calculator, etc.

STRATIFIED SAMPLING

Here the population is firstly divided into categories and the number of

people in each category is found out.

The sample is then made up of these categories in the same proportions

as they are in the population using % or a scaling down factor.

The required numbers in each category are then selected randomly.

The whole population = 215 Lets say the sample is 80 so we divide each

Age Male Female amount by Age Male Female

215/80

0-29 34 26 0-29 13 10

=2.6875

30-59 46 54 30-59 17 20

60- 19 36 60- 7 13…read more

### Slide 5

Here are 4 scatter diagrams and some

Scatter diagrams questions that may be asked about them

A C E G

B D F H

Strong Weak No Strong

As B increases As D increases NoNolink

relationship

between As H increases

positive positive correlation negative

so does A so does C variables

between E and F G decreases

correlation correlation correlation

Describe the type Describe what each diagram shows

of correlation in

Give examples of what

each diagram

variables A H could be

Draw a line to best A = No. of ice creams sold , B = Temperature

show the link

C = No. of cans of coke sold , D = Temperature

between the

two variables E = No. of crisps sold , F = Temperature

G = No. of cups of coffee sold , H = Temperature…read more

### Slide 6

Pie charts Draw a pie chart for the following information

Step 1

Find total

Step 2

Divide 360 by total to

find multiplier

Step 3

Multiply up all values

to make angles

900 360 ÷ 900 = 0.4 3600

Step 4

Check they add up to

160

C5 3600 and draw the Pie

C4

Chart

350 BBC 1

1660

ITV 0 Pie Chart to show the favourite

122

TV channels at Saint Aidan's

210

BBC 2…read more

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