Psyc312-8
Card Set Information
Author:
ctryhurn
ID:
25285
Filename:
Psyc312-8
Updated:
2010-06-30 09:04:32
Tags:
psyc
Folders:
Description:
psyc
Show Answers:
For which scales can a mean be calculated
Nominal
Interval
Ratio
For which scales can a median be calculated
Ordinal
Interval
Ratio
For which scales can a mode be calculated?
Nominal
Ordinal
Interval
Ratio
Advantages & Disadvantages of using the mean
easily manipulated algebraically
reliable because it takes into account every measure of a data set
greatly affected by extreme scores
Advantages & Disadvantages of Median
little influence by extreme scores
reasonable estimate of the center of a distribution
may not be good to ignore extreme values
Advantages & Disadvantages of Mode
not influenced by extreme scores
may not represent the scores
ignores extreme values completely
How to calculate IQR?
Find the median location (n+1)/2
Find quartile location (ML+1)/2
Find Q1 & Q3 (low score + QL; high - QL)
IQR= distance btwn Q3 - Q1
Outliers
: Q3+ (1.5 x IQR); Q1-(1.5 x IQR)
Empirical Rule...
68-95-99.7 within 3 standard deviations of the mean
Deviation
the difference btwn each score and the mean of the data set
Variance
single number representing the average amount of variation in a data set
Standard deviation
Measure of the spread of scores out from the mean of the sample