Comparisons Of Central Tendency Averages Flashcards
Mean
Takes jn all data values so it can be easily influenced by high or low values , thus susceptible to outliers
Median , mode , midrange
Less sensitive to outliers
Median good and decent if values not relative to mean
Mode only used for high frequency data
Midrange is also susbcitbke to outliers don’t use , assumes data symmetrical!!!
Calculating median from frequency table
GROUPED DATA
Remember if even frequency it will be an average of both middle values need to remember this
2) IF ITS GROUPED THEN JUST DIVIDE BY 2 DONT ADD ONE
How to compare box plot
1) median , higher median means higher average
2) IQ range, shows how much or less spread out data is
3) range
Standard deviation for grouped values ?
USE MIDPOINT AS VALUE FOR X THE
= f* x^2 then do the rest
Outliers
2 plus minus SX from mean or
1.5 IQR from quartiles
Scatter diagrams IMPORTSNT about correlation
Correlation does not imply causation
How to better data
Clean it , use different sample techniques with better ways of doing em , better collecting method
Also if straitifying straitify by more regions etc
Remember if they don’t already give class width what you have to do for adjustment?
Round it by upper bounds and ADJUST !