STATISTICS Flashcards
What is standard deviation a measure of?
Spread
Why is standard deviation better than range?
Not affected by extreme values or outliers
What is nominal data?
Discrete categories with no concept of order
Eg: gender and eye colour
What is ordinal data?
Rank them, has a value with it but not quantitative data
What does a normal distribution curve look like?
Symmetrical, bell shaped curve
Mode= mean= median
What is a positively skewed distribution?
Asymmetrical
Peaks at the start of graph
Mode
What is a negatively skewed distribution?
Asymmetrical
Peaks at the end of the graph
Mean< median< mode
What is a null hypothesis?
There is no relationship between two variables being studied
Eg: The score a pupils receives in the topic will not be effected by the time of day it takes place
What is an alternative hypothesis?
There is a relationship between two variables being studied
Eg: The score a pupil receives if the lesson is in the afternoon will be higher than that in the morning
What is the significance level of a test?
How unlikely the test statistic needs to be before you reject the null hypothesis.
The smaller the significance test, the stricter the test
What does non parametric mean?
Does not have a normal distribution
What type of measures design is the Chi squared test designed for?
Independent
What type of data is the Chi squared test ideal for?
Nominal
For the Chi squared test, how do you work out expected frequency?
Row total x Column total/ grand total
After working out the expected frequency for Chi squared add them to your table, what is the next calculation?
(observed-expected)2/ expected
Add all the values together
