Modual 4

Question 1

How do you use the straight-line graph formula to plot a graph with the formula - y=2x+1

Answer 1

1) c = 1, so put the first dot on y = 1
2) go along 1 square > and then up 2 squares because m = +2
3) repeat step 2 in both directions

Question 2

What is the straight-line graphs formula?

Answer 2

y = mx + c

Question 3

What is discrete data?

Answer 3

Data which only has whole numbers

Question 4

Give a example of discrete data

Answer 4

Humans, cant have 5.5 people

CD’s, cant have 7.2 CD’s

Question 5

Where does the line of best fit go?

Answer 5

through the middle of as many of the plotted points as possible with all of the other plotted point very close to it

Question 6

What does a positive correlation look like?

Answer 6

Bottoms left - top right /
/
/
/
/
/

Question 7

What does a negative correlation look like?

Answer 7

bottom right - top left

Question 8

What does no correlation look like?

Answer 8

the dot are all over the graph and there is no-where to put a line of best fit

Question 9

What is random sampling?

Answer 9

Ask random people

Question 10

What is systematic sampling?

Answer 10

start with a random selection of answers

select every 10th or 100th answer

Question 11

What is stratified sampling?

Answer 11

Pick a group of people

than pick random people from that group

Question 12

What is quota sampling?

Answer 12

ask people that best reflects the whole population

e.g. male/female, adults/children, rich/poo

Question 13

What is a histogram?

Answer 13

A bar chart apart from the bar’s can be different width’s

Question 14

What is the rules about histograms?

Answer 14

• not the height but the width that matters

Question 15

If the 55-65 bar of a chart represents 36 people and contain 4 dotted squares, how many people are in the 80-90 group if it has 14 dotted squares?

Answer 15

14x9 = 126people

each square = 9 people because 36/4=9