Descriptive Statistics Flashcards Preview

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Flashcards in Descriptive Statistics Deck (17):
1

Nominal

exhaustive and mutually exclusive categoies
(categorical)

2

ordinal

ordered
(categorical)

3

interval

equal distances between scores
calculate differences but not proportions
(discrete or continuous)

4

Ratio

interval + a true zero
percent correct, 50% is twice as accurate 25%
(discrete or continuous)

5

mean

interval, ratio
(central tendency)

6

median

ordinal, interval, ratio
(central tendency)

7

mode

all types
(central tendency)

8

min, max, range, interquartile range

measures of variability

9

standard deviation

dispersion of scores around the mean

10

standard error of the mean

How far is the sample mean likely to be from the population mean?

11

visualization of data

pie chart, scattor plot, bar graph, line graph

12

normal distribuation

"gaussian curve"
largest number of observations at the center
2/3 of observations will fall within 1 SD of mean

13

skewed

more extreme scores in one direction

negatively skewed more scores towards right

named by tail side

14

kurtosis

peakedness and shape of tails

15

z score

how many SD above or below the mean

relate normal distribution to other z scores

16

t distrubuation

shift and scaled so that m = 50 and sd =10
this is used for small sample sizes and unknown population standard dev

17

outliers

set a criteria a priori based on meausres and literature
trimming of reaion times is common. - like more than 2.5 SD lower than mean.

NEVER remove data without minially describing