Descriptive Statisitcs

Question 0

What are the types of Frequency Distributions?

Answer 0

1. Histogram
2. Polygons
3. Bar Graphs

Question 1

Frequency distribution

Answer 1

Distribution showing a frequency for each value of a variable.

Question 2

what is a frequency?

Answer 2

A count of how many times a value occurs

Question 3

Nominal

Answer 3

NO: #s are not meaningful
NO: spaces between #s ≠
NO: |0|
Ex: gender, hair color

Question 4

Ordinal

Answer 4

YES: #s are meaningful
NO: space between #s are ≠
NO: |0|
Organizing categories

Question 5

Interval Data

Answer 5

YES: #s are meaningful
YES: spaces between #s are =
NO: |0|

Question 6

Ratio

Answer 6

YES: #s are meaningful
YES: spaces between #s are =
YES: |0|
Zero point

Question 10

Positively skewed data

Answer 10

high % of scores are at the low end
tail to the right
M is higher than the Mdn

Question 11

Negatively Skewed Data

Answer 11

Large % of scores at the high end of distribution. Tail to the left.
M is lower than the Mdn

Question 12

If Mean, Median, & Mode are equal

Answer 12

Symmetrical, no skew, both sides are equal, normal bell shaped curve.

Question 13

Kurtosis

Answer 13

The degree to which scores cluster around the mean or are spread out over a wide range with many extreme scores.
It is a measure of the flatness or peakedness of a distribution.

Question 14

Mesokurtic

Answer 14

Rolling hill.
Symmetrical, mesokurtic is a normal curve bell curve.
M, Mdn, Mode are equal

Question 15

Platykurtic

Answer 15

Plato
Flat top, many scores at the extreme ends.
A lot of scores around the M but of equal purportionatley. a lot of scores at extreme ends

Question 16

Leptokurtic

Answer 16

Peak or summit
Long tails, scores bunch up at the Mean.
M is Mode,

Question 17

Measures of Central Tendency

Answer 17

Most typical or representative of the entire group.

Question 18

Descriptive Statistics versus Inferential Statistics

Answer 18

Describes the variables

Inferential Infers about the relationship between variables

Question 19

Mode

Answer 19

Most frequently occurring scores.
5, 10, 1, 1, 1
1 = Mode

Question 20

Bimodal

Answer 20

Two scores occur at the highest frequencies.

Question 21

Multi Model

Answer 21

All have to occur with equal frequency

Question 22

Median

Answer 22

The score that divides the distribution directly in half where 50% of the scores are about it and 50% below it.
Odd # data middle most score.
Even # data at 2 middle scores and divide by 2

Question 23

Mean

Answer 23

M = the sum of all individual scores
divided by n: total scores
EX = 40
EX/N = 40/4 = 10

Question 24

N = all scores in a population

Answer 24

n = all scores of a different group

Question 25

Mode:

Answer 25

Can be used with all scales of measurement.

ONLY one that can be used with NOMINAL DATA

Question 26

Median

Answer 26

Can be used for Ordinal, Interval, and Ration Data

MOST appropriate for ORDINAL DATA

Question 27

Special Considerations on the Mean

Answer 27

Measure of central tendency generally favored by psychologists
•Outliers: M is heavily influenced by extreme scores
Ex: how many sex partners would you like to have the next 30 years?

Question 28

Measures of Variation

Answer 28

Range: subtract the highest score and lowest score

100-1 = 99

Question 29

Variance, var, s2:
# that represents the total amount of variation in the distribution, Larger the variance the more total spread of scores.

Answer 29

s2=Sum of all (take each score subtract from the mean, square it, then add it up.) divided by n-1.
not usually reported.

Question 30

Standard Deviation:

how much on average scores deviate from the mean.

Answer 30

variance's square root.
where:
X= each score
M = the mean or average
n= the number of values
E= means we sum across the values

Question 31

What makes the SD big or small?

Answer 31

relative to what you are measuring.
if the average age in class is 22 years old, sd is 0 means all ages are 22.

Question 32

Mean

Answer 32

Can be used for Interval and Ratio Data but NOT for ORDINAL OR NOMINAL DATA
Ex: gold, silver, bronze cant have 3.5

Question 33

Bar graphs

Answer 33

There are spaces between the bars indicate spaces between #s are ≠. Appropriate for Nominal or Ordinal data.

Question 35

Appropriate distributions to be used with Interval and Ratio data?

Answer 35

Histogram

Polygon