# Shared Flashcard Set

## Details

CJ Methods Test #2
test #2 with Dr. Exum
24
Criminal Justice
10/31/2012

Term
 What level(s) of measurement is the frequency distribution designed to describe?
Definition
 nominalordinalratio
Term
 In a bar graph the 'bars':
Definition
 don't touch
Term
 In a histogram the 'bars':
Definition
 touch/are continual
Term
 What level(s) of measurement is a bar graph designed to describe?
Definition
 nominal/ordinal
Term
 What level(s) of measurement is a histogram designed to describe?
Definition
 ratio
Term
 Normal distribution
Definition
 bell-shapedone peak with two tailsright side is mirror image of left
Term
 Bi-modal distribution
Definition
 2 peaks (set of clusters)
Term
 Uniform (flat) distribution
Definition
 roughly the same # for every attribute
Term
 What are the measures of central tendency?
Definition
 meanmedianmode
Term
 mean
Definition
 "the average""the value around which all deviations sum to zero"great measure; use it when you candesigned for ratio level measureshighly influenced by skewness and outliers-still mathematically correct-but can be misleading
Term
 median
Definition
 • the attribute falling in the middle of a rank ordered set of scores • attribute that falls at the 50th percentile • EX- data from 7 people in rank order (odd number) 0,0,1,2,3,7,8 median= attribute at 4th position (2)• EX- data from 8 people in rank order (even number 0,0,1,2,3,7,8,10 median=average of 4th & 5th positions• average of 2 and 3= 2.5 median• not as functional as the mean• Not sensitive to outliers/skewness• The variable must be ordinal or ratio (must put attributes in rank order; you cant rank nominal)
Term
 mode
Definition
 • simplest measure of central tendency• the attribute that occurs most often (has the highest frequency) NOT how many times it occurs • Not as functional as the median (or mean)• A variable can have more than 1 (bi-modal)• Not sensitive to outliers/skewness• The only central tendency measure you can use with nominal data
Term
 what are the measures of variability?
Definition
 rangestandard deviationvariance
Term
 range
Definition
 o -simplest measureo -Range=highest-lowesto -Larger range=more variability -Weakness of the range -Sensitive to outliers -ignored the variability of the scores “in the middle”
Term
 What are the 3 criteria for determining causality?
Definition
 temporal ordercorrelationrule out spuriousness
Term
 What does random assignment mean?
Definition
 Randomly assigned to control group/experimental group
Term
 what do measures of central tendency do?
Definition
 # that tells us where a variables attributes tend to fall
Term
 off-line outliers
Definition
 make a football fatterpearson r will be lower (i.e.- weaker) b/c of its outlier
Term
 "on-line" outliers
Definition
 make football skinnierpearson r will be higher (i.e. stronger) b/c of this outlier
Term
 3 rules for using the measures of central tendency
Definition
 1. use mean whenever appropriate -ratio data that is normally distributed (or approximately normal)2. if you cant use the mean, use the median (if appropriate)-ordinal data, or ratio data that are highly skewed or have outliers3. if you cant use the median use mode-when you have nominal data
Term
 "double blind" experiments
Definition
 -participants dont know what group they are in-researcher collecting/analyzing data doesn't know-3rd party knows but doesn't reveal info until data are analyzed
Term
 statistically significant
Definition
 does not necessarily mean big instead it says the finding is REAL, we believe it exist in our population
Term
 correlation matrix
Definition
 a table showing the correlation between all possible combinations of variablesunivariate analysis/statistics- 1 variable bivariate analysis/statistics- 2 variablesmultivariate analysis/statistics- 3+ variables
Term
 attrition (morality)
Definition
 is the loss of participants over time due to refusal to participate, inability to reestablish content, death, etc.
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