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| What level(s) of measurement is the frequency distribution designed to describe? |
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Definition
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Term
| In a bar graph the 'bars': |
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Definition
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Term
| In a histogram the 'bars': |
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Definition
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Term
| What level(s) of measurement is a bar graph designed to describe? |
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Definition
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Term
| What level(s) of measurement is a histogram designed to describe? |
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Definition
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Term
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Definition
bell-shaped
one peak with two tails
right side is mirror image of left |
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Definition
| 2 peaks (set of clusters) |
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Term
| Uniform (flat) distribution |
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Definition
| roughly the same # for every attribute |
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Term
| What are the measures of central tendency? |
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Definition
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Term
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Definition
"the average"
"the value around which all deviations sum to zero"
great measure; use it when you can
designed for ratio level measures
highly influenced by skewness and outliers
-still mathematically correct
-but can be misleading |
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Term
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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) |
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Term
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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 |
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Term
| what are the measures of variability? |
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Definition
range
standard deviation
variance |
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Term
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Definition
o -simplest measure
o -Range=highest-lowest
o -Larger range=more variability
-Weakness of the range
-Sensitive to outliers
-ignored the variability of the scores “in the middle” |
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Term
| What are the 3 criteria for determining causality? |
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Definition
temporal order
correlation
rule out spuriousness |
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Term
| What does random assignment mean? |
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Definition
| Randomly assigned to control group/experimental group |
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Term
| what do measures of central tendency do? |
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Definition
| # that tells us where a variables attributes tend to fall |
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Term
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Definition
make a football fatter
pearson r will be lower (i.e.- weaker) b/c of its outlier |
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Term
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Definition
make football skinnier
pearson r will be higher (i.e. stronger) b/c of this outlier |
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Term
| 3 rules for using the measures of central tendency |
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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 outliers
3. if you cant use the median use mode
-when you have nominal data |
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Term
| "double blind" experiments |
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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 |
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Term
| statistically significant |
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Definition
| does not necessarily mean big instead it says the finding is REAL, we believe it exist in our population |
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Term
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Definition
a table showing the correlation between all possible combinations of variables
univariate analysis/statistics- 1 variable
bivariate analysis/statistics- 2 variables
multivariate analysis/statistics- 3+ variables |
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Term
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Definition
| is the loss of participants over time due to refusal to participate, inability to reestablish content, death, etc. |
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