Flashcards in Psychology 202 - Test 1 Deck (36):

1

## data

### information

2

## statistics

### branch of mathematics focused on organization, analysis, and interpretation of a group of numbers

3

## descriptive statistics

### used to describe a group of numbers from a study

4

## inferential

### used to draw conclusions from collected data

5

## variable

###
characteristic of something or someone that can have different vaules

i.e. people, [usually] mind

6

## constant

###
if the characteristic does not/can not vary

- dependent on perspective

7

## values

### numbr or category

8

## score

###
particular value on a variable

- tells how much there is of what is being measured

9

## equal-interval variable

###
a variable in which the numbers stand for approximately equal amounts of what is being measured

i.e. in stress rating, difference between 4 & 6 is the same as the difference between 7 & 9

10

## ratio scale

###
used if the equal-interval variable has an absolute zero point

i.e. number of siblings > zero means something and is important

11

## absolute zero point

###
value of zero on the variable indicates complete absence of the variable

i.e. number of siblings > zero = no siblings

12

## rank order variable

###
a variable where numbers stand ONLY for the relative ranking

- ordinal variables

- provides less info/less accurate than equal-interval but sometimes easier/only info available

i.e. olympics (1,2,3) but 1 & 2 can be close while three was far behind them

13

## nominal variable

###
variable in which the values differ as names or categories

i.e. favorite sports team

*can go from nominal to numeric but not the other way around

14

## discrete variable

### specific values and nothing in between

15

## continuous variable

### has infinite number of values in between any two values

16

## population

###
the entire group of people that is studied

- can range from small to the entire world depending on the question

17

## sample

###
a subset of the population

- small/more manageable group to study

-(hopefully) identical to population > generalizability

18

## frequency table

### table that lists all values that are possible along with the number of cases that have that value

19

## relative frequency table

###
tells frequency AND frequency relative to other scores

- divide number of cases in each value by total number of cases

20

## histogram

###
graphic representatio of frequency of scores

- x = possible values

- y = number of cases

21

## number of peaks (histogram)

###
1 peak = unimodal

2 peaks = bimodal

3+ peaks = multimodal

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## symmetrical distributions

### roughly equal scores on both sides of the peak

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## skewed distributions

###
unequal scores on each side of the peak

- positively skewed > more scores on left side

- negatively skewed > more scores on the right side

24

## normal curve

###
symmetrical, bell shaped curve that has changes in curve direction at exactly 1 standard deviation above and 1 standard deviation below the mean

- theoretical distribution

- mode, median, and mean are all exactly the same number

- Middle point = average point = most frequent point

- more scores you have = closer you get to normal distribution

- assume data would look like normal curve if we had enough

- 68.2% = 1 SD

- 95.4% = 2 SD

- 99.7% = 3 SD

25

## platykurtic

###
most values have roughly the same frequency

- upside down plate

26

## leptokurtic

###
very few values have a high frequency

- tower

27

## measure of central tendency

###
single number that we use to describe a distribution of scores

- representative of all scores

28

## mean

###
mathematical average of a group of scores

- μ = population, M = sample

- mean = Σx/N

- most stable measure of central tendency

- takes all scores into account

- can be value no one got

- incredibly sensative to outliers

29

## mode

###
most frequent score in a distribution

- only measure that can be used with nominal data

- says nothing about other scores

-doesn't tell the placement of the score

30

## median

###
score in the middle of a distribution

- scores in order from smallest to largest and find middle score

- can be the same as mode

- can be score no one has/received

- does not mean there is equality in the range

31

## variability

### the amount of variation in a distribution of scores

32

## range

###
the difference between the highest and lowest score

- very unstable

- no additional stats calculated

33

## variance

###
measure of variability that considers how different each score in a distribution is from the mean

- extremely important in stats

- population = δ

- sample = SD

- variance = Σ(x - M)²/N

- SS = Σ(x - μ)²

34

## standard deviation

###
the average amount that a set of scores differ from one another (how much scores vary)

- population =

- sample = SD

- standard deviation = √Σ(x - μ)²/N

35

## z-score

###
number of standard deviations above or below the mean an actual score is

- standardizes scores

- z = (x - M)/SD

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