What are the 4 kinds of data?
Nominal
Ordinal
Interval
Ratio
What is nominal data?
Categorical, cannot be ordered
What is ordinal data?
Order can be defined
What is interval data?
Order can be defined
Differences between values can be quantified
What is ratio data?
Order can be defined
Differences between values can be quantified
Ratios between values can be quantified
Frequency distribution curves which are not symmetrical are said to be…
Skewed
For a normal distribution what al have the same values?
Mean
Median
Mode
What does positively skewed distribution look like?
Peak on the left side
How do you decide the number of classes to group data into?
Square root total number of data values
What is the nearest neighbour index?
Measures the extent to which a spatial distribution is ‘clustered’
What do Rn values mean?
Nearest neighbour index values:
0= clustered
2.15= regular
What is location quotient?
A measure of how concentrated a particular factor is within a certain area, eg a demographic group.
How do you interpret location quotient?
1=factor is represented in your area the same conc as the wider area, >1= has higher average conc, below =lower
I’m spearman’s, what is d?
Difference in ranks.
What are 3 tests used to decide whether there’s a significant difference between 2 sets of values?
Students t test
Mann Whitney U test
Chi squared (observed vs theoretical)
What does the students t test do?
Compares the means of 2 sets of data to decide if there’s a significant difference between them
What’s different about the students t test?
It’s a parametric test- should only be used when the data follows a normal distribution.
What does the Mann Whitney U test do?
Compares the median values to determine whether there’s a significant difference between 2 data sets.
(Like t test but for medians)
Why is the Mann Whitney u test flexible?
Non parametric- makes no assumption of data being normally distributed.
What is the degrees of freedom for spearman’s ?
The number of paired values in the data set.
What is the significance value?
The chance of the result happening randomly
What significance level do u use in geography?
0.05
What do u do w the results lf the Mann Whitney u test?
Smaller u value less than critical value: null hypothesis rejected