Psychology 202 - Test 1

Question 1

data

Answer 1

information

Question 2

statistics

Answer 2

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

Question 3

descriptive statistics

Answer 3

used to describe a group of numbers from a study

Question 4

inferential

Answer 4

used to draw conclusions from collected data

Question 5

variable

Answer 5

characteristic of something or someone that can have different vaules
i.e. people, [usually] mind

Question 6

constant

Answer 6

if the characteristic does not/can not vary

- dependent on perspective

Question 7

values

Answer 7

numbr or category

Question 8

score

Answer 8

particular value on a variable

- tells how much there is of what is being measured

Question 9

equal-interval variable

Answer 9

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

Question 10

ratio scale

Answer 10

used if the equal-interval variable has an absolute zero point
i.e. number of siblings > zero means something and is important

Question 11

absolute zero point

Answer 11

value of zero on the variable indicates complete absence of the variable
i.e. number of siblings > zero = no siblings

Question 12

rank order variable

Answer 12

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

Question 13

nominal variable

Answer 13

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

Question 14

discrete variable

Answer 14

specific values and nothing in between

Question 15

continuous variable

Answer 15

has infinite number of values in between any two values

Question 16

population

Answer 16

the entire group of people that is studied

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

Question 17

sample

Answer 17

a subset of the population

• small/more manageable group to study
• (hopefully) identical to population > generalizability

Question 18

frequency table

Answer 18

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

Question 19

relative frequency table

Answer 19

tells frequency AND frequency relative to other scores

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

Question 20

histogram

Answer 20

graphic representatio of frequency of scores

• x = possible values
• y = number of cases

Question 21

number of peaks (histogram)

Answer 21

1 peak = unimodal
2 peaks = bimodal
3+ peaks = multimodal

Question 22

symmetrical distributions

Answer 22

roughly equal scores on both sides of the peak

Question 23

skewed distributions

Answer 23

unequal scores on each side of the peak

• positively skewed > more scores on left side
• negatively skewed > more scores on the right side

Question 24

normal curve

Answer 24

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

Question 25

platykurtic

Answer 25

most values have roughly the same frequency

- upside down plate

Question 26

leptokurtic

Answer 26

very few values have a high frequency

- tower

Question 27

measure of central tendency

Answer 27

single number that we use to describe a distribution of scores
- representative of all scores

Question 28

mean

Answer 28

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

Question 29

mode

Answer 29

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

Question 30

median

Answer 30

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

Question 31

variability

Answer 31

the amount of variation in a distribution of scores

Question 32

range

Answer 32

the difference between the highest and lowest score

• very unstable
• no additional stats calculated

Question 33

variance

Answer 33

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

Question 34

standard deviation

Answer 34

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

Question 35

z-score

Answer 35

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

• standardizes scores
• z = (x - M)/SD

Question 36

z-scores > percent to value

Answer 36

• go to closest percent
• find percent and look at corresponding z-score
• invert z-score equation