Statistics

Question 0

Descriptive (statistics)

Answer 0

Mean, median, mode, standard deviation.
Used to organize and summarize data in a meaningful way (ex: frequency distributions, measures of central tendency, measures of variability, …)

Question 1

Definition & why we use it

Answer 1

Used to help support research findings and hypothesis.
Data must be collected and evaluated correctly.
Reliability (is data consistent?) and validity (does it measure what it is supposed to?)!

Question 2

Inferential (statistics)

Answer 2

Assumptions; guesses; use measurements from a sample to draw conclusions about a larger, measured population.
Determines whether outcomes are likely to be more than nuts chance and whether they can be legitimately generalized to a larger population.
Statistically significant.
Always dealing with probabilities (not factual) NOT certainties.
Must replicate.

Question 3

Chance

Answer 3

.001 best
.01 better
Less than 5% for it to happen by chance

Question 4

Nominal (data)

Answer 4

Numbers that are used to name or categorize (categorical info)

Question 5

Ordinal (data)

Answer 5

Numbers represent serial position; greater or lesser than.
Mode and median generally reported.
Differences between RANKINGS are not always the same.
Number relationships; superiority and inferiority.

Question 6

Interval scale (data)

Answer 6

Consistent units of measurement, equal spacing between, allows for mathematical operations.
No true zero point.
Intervals between numbers are equal.

Question 7

Ratio scale (data)

Answer 7

Same consistent units of measurement as in the interval scale but with the added property of a true zero point (complete absence of the thing being measured).
Compare scores in terms of ratios.
Ex: time, length, speed….

Question 8

Frequency distribution

Answer 8

Lists scores in ascending order, allows us to see HOW OFTEN A CERTAIN SCORE SHOWS UP.
Set up in arable format.
Good for summarizing data; typically a visual component (graph)

Question 9

Histogram

Answer 9

Bar graph that uses vertical bars that touch.

Way to graphically represent a frequency distribution.

Question 10

Frequency ploygon

Answer 10

Method of graphically representing a frequency distribution.

Line graph.

Question 11

Positive skew

Answer 11

Most people/scores are LOW.
The few high scores “skew” the graph.
Skew = slang

Question 12

Negative skew

Answer 12

Most people/score are HIGH.

Skew indicates whether tail is.

Question 13

Mean is larger than median (central tendency)

Answer 13

Pulls distribution to the right - positive skew

Question 14

Mean is smaller than median (central tendency)

Answer 14

Pulls distribution to the left - negative skew

Question 15

Measures of central tendency

Answer 15

Mode, median, mean

Question 16

Measures of variability

Answer 16

Presents info about the spread of scores in a distribution.

Question 17

Variance

Answer 17

How clustered or spread out individuals scores are around the mean.
The lower the level, the better.

Question 18

Standard deviation

Answer 18

The average distance of scores around the mean.

Question 19

Equation for variance

Answer 19

Σ(x-x̅)² divided by (n-1)

Question 20

Equation for standard deviation

Answer 20

After finding variance (Σ(x-x̅)² divided by (n-1)), square root the variance.

Question 21

Calculating variance

Answer 21

Find mean. 
Subtract mean from each score.
Square each.
Find sum of squared scores.
Divide the sum by total number of scores.

Question 22

Σ(x-x̅)² divided by (n-1)

What does each symbol represent?

Answer 22

n = # of scores
x = score
x̅ = mean 
Σ = sum of

Question 23

Standard normal curve

Answer 23

Symmetrical distribution forming a bell-shaped curve (mean, median, and mode are all equal and fall in the exact middle).
Used to tell exactly what % falls between any 2 points.
Tells exactly where a person stands relative to everyone else in the distribution.

Question 24

Z-scores

Answer 24

A number that shows an individual score’s deviation from the mean (written in standard deviation form).

Question 25

Calculating & equation of z-score

Answer 25

Subtract mean from score and divide it by SD.

Z = (x-x) divide by standard deviation

Question 26

Positive z-score

Answer 26

Indicates that score is above mean.

Question 27

Negative z-score

Answer 27

Indicates that score is below mean.