Stats Flashcards
What are the 3 types of average?
Mean, median mode
How to find the mean?
Add all the numbers together and multiply by how many numbers there are
What is the median and how do you find it?
It is the middle number.
Write all the numbers in order and then pick the middle number. If there are two in the middle, you find the mean or those two.
Basically just half way in between them.
What is a summary question?
Focus on the whole group
Eg: I wonder what the most popular TV show is
What is a comparison question?
Compared 2 groups.
Eg: I wonder if year 9 students tend to be more active than year 10 students
What are relationship questions?
Compare two measurement variables
Eg: I wonder if armspan is the same as height.
What kind of question is this:
“I wonder how many people walked to school”
Summary
What kind of question is this:
“I wonder if most boys are taller than most girls”
Comparison
What kind of question is this:
“I wonder why younger students run more at lunchtime”
Can’t be answered from the data
What kind of question is this:
“I wonder if most students armspan is the same as their height”
Relationship
How is relationship data graphed?
On a scatter plot with a trend line through it. A scatter plot has measurement variables on both the x and y axis of the plot and they relate to each other as you graph them.
A relationship can be described as positive if?
The trend line goes up /
Negative if it goes down \
The range and quartiles give us information about the?
Spread of the data
Range?
Spread of the whole data set. Difference between the minimum and maximum values.
Lower quartile?
The median of the lower half of the data. 1/4 of the data is below it.
Upper quartile?
Median of the upper half of the data. 1/4 of data is above it.
Inter quartile range?
The difference between the UQ and the LQ.
IQR = UQ-LQ
To find quartiles you?
Find the median, and then find the median of the bottom half below the median, and the median of the top half above the median
3 steps for a stats conclusion?
- Answer the question
Eg: in conclusion, from this data I can see that - Justify your answer
Eg: I know this because - Relate to context
Eg: this makes sense to me because
To be able to make the call as to whether on groups data is different to the other group we need to compare the?
Box and whisker graphs
To make a box and whisker graph you?
Draw a line at the lowest date point, a line at the LQ, a line at the median, a line at the UQ and a line at the highest date point. Then draw a box from the LQ to the UQ with the median in it. Then connect whiskers to the highest and lowest data points.
How can you tell from a box and whisker graph that one groups data is different to the other groups you must?
Be able to see that the median of one groups data is OUTSIDE AND ABOVE the IQR box of the other set of data.
What kind of shape is a graph with one peak?
Unimodal
What kind of shape is a graph with two peaks?
Bi-modal
What kind of shape is a graph with a bell shaped curve?
Normal curve
What kind of shape is a graph where all the data comes to roughly the same height?
Uniform
What kind of shape is a graph where most of the data is to the right of the highest point?
Right skew
What kind of shape is a graph where most of the data is to the left of the highest peak?
Left skew
What kind of shape is a graph where there is a scattering of data to the right?
Long tail to the right
What kind of shape is a graph where there is a scattering of data to the left?
Long tail to the left
What are the 2 types of data?
Qualitative (categorical) and quantitative (numerical).
What kind of data is qualitative/categorical data?
Data that is:
- not numbers
- always discrete
Eg: favourite colours of a group
What are the two types of quantitative/numerical data and what is the difference between them?
Discrete:
- can be counted
Eg how many pets do you have
Continuous:
- is measured
Eg height, weight etc.
What is mode?
The most common number
