Maths unit one

180 degree angles:

• Interior
• Striaght lines
• Triangles

360 degree angles:

• Round a point
• Quadrilaterals
• Exterior angles

Equal angles:

• Opposite
• Corresponding
• Alternate
• Parallel lines

N=number of sides

(n-2) x 180 degrees

Triangle = 180 degrees

Quadrilaterals = 360 degrees (180 + 180)

Pentagons = 540 degrees (360 + 180)

etc.

Random sampaling:

People are chosen at random. e.g names picked from a hat. Every member of the population has an equal chance of being chosen.

Advantage:

• It's fair.

Disadvantage:

• Very time consuming.
• Often impractical

Systematic sampling:

Members of the populatipn are chosen at regular intervals, such as every 100th person.

Advantage:

• You are unlikely to get a biased sample.

Disadvantage:

• It's not strictly random. Some people can't be picked once you've decided where to start the list.

Straified sampling:

When the population is composed of different groups of people.

Advantage:

• It's the best way to reflect the population accurately.

Disadvantage:

• It's time consuming.
• You have to limit the number of relevant variables.

Hey diddle diddle

The medians in the middle

You add and divide for the mean

The mode is the one that appears the most

And the range is the difference between

The mean is the average.

• Add up all of the values to find a total.
• Divide the total by the number of values there are.

e.g

2 2 3 5 5 7 8. There are 7 values.

2+2+3+5+5+7+8=32

32/7=4.57.

The mean is 4.57.

The median is the middle value.

• Put all of the values into order.
• The median is the middle value.
• If there are two values in the middle, find the mean of these two.

e.g

5 7 2 3 8 2 5

Ordered: 2 2 3 5 5 7 8

The median = 5

5 7 2 3 8 2 5 2

Ordered: 2 2 2 3 5 5 7 8

3 and 5 are in the middle. So 3 + 5 = 8. 8/2= 4. The median is 4. Notice that 4 is in the middle of 3&5

The mode is the most frequent value.

• Count how many of each value appears.
• The mode is the value that appears more time than others.
• You can have more than one mode.

e.g

2 2 3 5 5 7 8.

two 2's, one 3, two 5's, one 7, one 8

2 and 5 are the mode's

The range is the difference between the lowest and highest value.

• Find the highest and lowest values.
• Subtract the lowest value from the highest.

e.g

2 2 3 5 5 7 8

2 is the lowest. 8 is the highest.

8-2=6

6 is the range