POPULATION The set of all things or people being studied A group of people you want information...

POPULATION

• The set of all things or people being studied• A group of people you want information about• Examples– All the students of Fairwind– All the students of 806 and 808– All the salmon in Lake Ontario– All Canadians

CENSUS

• A method to collect data where ALL people in the population are surveyed

• Governments conduct censuses to ensure they get information about ALL citizens

• If you were to ask all classmates about their favourite movie, it would be a census

SAMPLE

• A PART of a population that is studied or surveyed

• Provides information about the entire population

• Should be representative (have qualities of the whole population) in order to have valid results

SURVEY

• A method of collecting data where people are asked questions

• Usually only asked to a sample of a population• A valid survey is one where the results are

good because the sample chosen and the method of asking questions are UNBIASED

BIAS

• UNFAIR• When a question is worded such that a

particular answer is favoured• When a surveying method is chosen that

unfairly represents the population• Leads to INVALID results

UNBIASED

• FAIR• Leads to VALID results• Proper sampling methods were used• Proper questions were used

TREND• A pattern or sequence• Trend up (generally heading up)• Trend down (generally heading lower)• Trend can be even (staying the same)• EX:– Climate change is an upward trend in average

temperature– The use of CDs is on a downward trend

INTERVAL

• Continuous data should be sorted into intervals in order to be shown on a histogram

• Ages of a population can be grouped by 10s– 0-9– 10-19– 20-29– 30-39

SCALE

• The numbers on the axes of a graph• Should count up by the same

amount each time (by 2s, 3s, or 10s, for example)

MEAN

MEDIAN

MODE

CATEGORICAL DATA

• Data that can be arranged into categories• Colours• Gender (male or female)• Types of something (flavours, fruit, sports…)• Favourite ‘something’ (movie, song, artist…)• Bar graphs are ideal

DISCRETE DATA• Data that can only be specific values • Data is counted• Class sizes can only be whole numbers (you can’t

have 22.5 students)• Shoe sizes - only whole and half sizes• Number of phone calls• Number of children in a family• Number of languages one speaks• Bar graphs are ideal• Scatterplots can compare two types of discrete sets

CONTINUOUS DATA

• Data can have any value• Often measurements of:– Height, Length, Width– Ages– Times– Temperatures

• Histograms are ideal

PRIMARY DATA

• Data collected by yourself• You have collected the data through:–Recording observations–Recording experiment data–Surveys you created–A census you created

SECONDARY DATA

• Data or information NOT collected by you• Data collected by others• Includes data from–Published books– Internet–Published graphs and charts provided by

your teacher

• Justify: prove it!• Interpret: What do you see? What does the

data mean?• Conclude (make conclusions): What are facts

from the data?• Outlier: one piece of data that is MUCH

greater or MUCH less than all others

SCATTERPLOTS

HISTOGRAMS

FREQUENCY TABLES

BAR GRAPH

CIRCLE GRAPH

LINE GRAPH

• Good for showing change over time