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P202 stats > First exam based on chapters 1-5 > Flashcards

First exam based on chapters 1-5 Flashcards

1
Q

Two meanings of statistics

A

formal & informal

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2
Q

Formal Statistics

A

a branch of math that focuses on organizing, summarizing, analyzing and interpreting data in a table or graph or numerically

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3
Q

Informal Statistics

A

numbers representing something

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4
Q

What do we use to analyze and interpret data?

A

Inferential stats

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5
Q

inference stats

A

make a inference or draw a conclusion from a sample from a population

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6
Q

Data

A

the info we gather from people, places and things

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7
Q

two types of formal stats

A

descriptive & inferential

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8
Q

descriptive stats

A

organize & summarize data

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9
Q

inferential stats

A

analyze & interpret data

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10
Q

variable

A

a characteristic that can assume different variables ex:height

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11
Q

value

A

a possible number or category a score can assume, these belong to a variable

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12
Q

score

A

the value of a variable for a specific person, place or thing

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13
Q

two types of variables

A

numeric & nominal

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14
Q

numeric variables (quantitative variable)

A

variables whose values are numbers, includes ordinal & interval

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15
Q

(equal) interval variables

A

the distance and difference between two sequential values is the same

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16
Q

ordinal variable

A

categorical variable includes categories divided into groups and are relatively ranked, ex: class rank

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17
Q

ratio variable

A

has an absolute zero

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18
Q

What is the one benefit of frequency tables?

A

they provide an organized overview of how often values occur in a group of scores

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19
Q

How do you calculate the percentage on a frequency table?

A

You divide the frequency by the total number of scores, N=30 and the frequency is 1 the perfect is 3.3%

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20
Q

where do the values and frequencies go on the frequency graph ?

A

the values go on the x-axis & the frequencies go on the y-axis

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21
Q

Frequency distributions

A

the shape of a frequency graph reflects the distribution of scores across values of a variable, characterize the pattern of data

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22
Q

unimodal

A

one highest point in the graph, this is the most frequent
(ex: scores on an IQ test)

23
Q

bimodal

A

two equally high points on a distribution (ex: age of people at a park)

24
Q

rectangular distribution

A

all values of the same frequency (ex: number of children in each grade)

25
Q

roughly symmetrical

A

one side of the face is the same as the other, a mirror image of the other

26
Q

positively skewed

A

skewed to the left side

27
Q

negatively skewed

A

skewed on the right side

28
Q

mean

A

average of the scores, add up all the scores and divide them by N

29
Q

Σ

A

sigma

30
Q

N

A

number of scores in our group of scores

31
Q

With means, averages should never be applied to ?

A

individuals, they are only calculated from individuals

32
Q

mode

A

most common value, it is the central tendency for nominal variables

33
Q

median

A

middle score, when arranged from lowest to highest

34
Q

variance table

A

4 columns, X, M, X-M, X-M^2

35
Q

X

A

score to the people in particular the raw score

36
Q

variance steps

A
  1. subtract the mean from each score
  2. square each of these deviation scores
  3. sum the squared deviation scores
  4. divide the sum of squared deviations by N
37
Q

standard deviation steps

A
  1. calculate the variance (SD^2)
  2. take the square root of the variance
38
Q

X is a

A

raw score

39
Q

Z is a

A

standardized score that talks in Standard deviation units, they are comparable and combinable

40
Q

Z score formula

A

Z=X-M/SD

41
Q

X-M is a deviation score what does that tell us?

A

It tells us how far away the X is away from the mean (M)

42
Q

What is the goal of the z-score?

A

to convert the raw score to standard deviation units

43
Q

What happens if the z-score is negative or positive?

A

Positive- the raw score is above the mean
Negative-the raw score is below the mean

44
Q

How are sample stats represented?

A

with roman letters like M, SD, SD2

Sample statistics can change from sample to sample because they are subsets of the population, each sample would be different

45
Q

How are population parameters represented?

A

Greek letters
mu (μ) -mean

σ-standard deviation these are fixed quantities

46
Q

conceptual interpretation

A

tells us the number of standard deviation units the raw score is above or below the mean

47
Q

How do you calculate a z score back to a raw score?

A

X= ZxSD + M

48
Q

substantive interpretation

A

applies it’s meaning to the specific scenario

49
Q

NHST (Null hypothesis significance testing) Step 1

A

Restate your research question into hypotheses about population,
Null hypothesis H(0)
Research hypothesis H(1)

50
Q

Null hypothesis

A

population 1 = population 2
meaning there is no difference

51
Q

Research hypothesis

A

population 1 mean is greater than (>) population 2 mean

52
Q

Population 2 in research hypotheses is?

A

people in general

53
Q

Step 2 of NHST

A

determine characteristics of the comparison distribution under the null hypothesis

54
Q

What do we do if our sample z-score exceeds the critical cutoff z-scores

A

we reject the null hypothesis

P202 stats (3 decks)

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