Maths Flashcards
What is a bar chart?
The height of the bar represents the frequency of each category
-leave space between bars
When would you use bar charts?
When data is NOT CONTINUOUS
When there are categories (observation)
What is a histogram?
Like a bar chart but…
- axis start at 0
- no spaces between bars
When would you use histogram?
Continuous data
E.g height, age, time
What is a scatter graph?
Represent relationships between data.
Plots NOT joined
When would you use scattergraphs?
Only to show correlation
What is a pie chart?
Alternative to bar chart
Each slice is a category
Divide freq by total freq * 360
When would you use a pie chart
Non continuous data
What is a line graph?
Alternative to histogram but a dot represents each bar
Line connects each dot
When would you use line graphs?
How something changed over time
Can be useful to compare 2+ conditions
What is standard deviation?
It tells us how SPREAD OUT the data is from the mean and gives us more info than just the average
What does a high sd mean?
Data is very spread out from the mean
What does a low sd mean?
Data is close to the mean
What does a sd of 0 mean?
All data values are the same
What are the 5 stages of calculating standard deviation?
Calculate the mean of the data
Subtract the mean from each value in the data
Square each result
Calculate the mean of squared differences (min one from the division value)
Square root the final number to give the sd
