IB Maths Exam

Population

All people we would like to collect data. Entire population

Sample

Smaller part of the population

Categories

Qualitative data ex: name, job etc.

Quantitative data

ex: age, height, etc which has numbers

a) continous (measure) - height

b) discrete (counting) - must use integers

Sampling:-

Simple/Random

“Sort out of a hat” number generator

Sampling:-

Convenience

“Lazy method” easiest way to get data. ex: choose the first six people that I meet

Systematic

Choose random starting point and fix an interval. ex: roll a dice set an interval, pick numbers accordingly.

Quota

Choose a sample that fits certain characteristic. ex: select people who play video games only

Stratified

Random sample that matches a proportion. ex: population of 100 - 60 men and 40 women

Grouped data

Intervals/classes

a) Discrete data

b) discrete data bar graph does not touch each other.

Relative frequency = absolute frequency/total

c) continuous data

IQR

Q3-Q1

Box Plot

Normal distribution - Median and average distributed equally 50%

Positively skewed - median < average

Negatively Skewed median> average

Outlier

Q1-1.5xIQR > Outlier

Q3+1.5xIQR < Outlier

Mean, median and mode

Mean - average

Mode - number with the highest frequency

Median the 50th percentile or the median quartile