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Statistical tests :newspaper: - Coggle Diagram
Statistical tests
:newspaper:
Spearman Rank Correlation Coefficient
:two_women_holding_hands:
VS
:two_men_holding_hands:
Compares the relationship between two variables
See whether there is a consistent change in the value of one variable as another variable increases/decreases
Assses how closely two variables are correlated
By comparing the rank order of the two variables
Hypotheses
Crop yield increases as fertiliser application increases :wilted_flower:
Noise levels decrease as distance from road increases :loudspeaker:
The number of moths increases as temperature rises :thermometer:
Chi Squared Test
:1234: :apple::apple:
Compares the frequencies of items/events
Used compare the frequencies or number of things in different groups are significantly different
Cannot be used for data that can be continously variable
Measured or calculated data :no_entry:
Hypotheses
The different management practices in a range of woodlands affect the numbers of dormice :mouse:
t-test
:straight_ruler: :banana: VS :pineapple:
Measured
Normally distributed data
Used to see if there's a significant difference between two means, where the data were measured
Mass
Length
wind speed
dissolved oxygen concentration
Only used if data is normally distributed and is hard will small sample sizes
If there's uncertainty use Mann Whitney U test
Hypotheses
The mean mass of lobsters is higher in areas where collection is banned :crab:
Wind speed is lower in a woodland than in a clearing :wind_blowing_face:
Mann- Whitney U test
:calling: :1234:
Calculated/Counted
See if there's a significant difference between two median values, where the data were counted (number of organisms/cars) or calculated such as diversity indices
Hypotheses
Fewer cars use a road when road charging is introduced :car::moneybag:
Biodiversity is higher in a hedge that is trimmed less frequently :bug: