Chapter 2 Frequency Distribution

Front 1

Define Statistics

Back 1

to simplify the organization and presentation of data

Front 2

Define frequency distribution

Back 2

organized tabulation of the number of individuals located in each category on the scale of measurement

Front 3

Frequency distribution duties

Back 3

allow you to see the location of any individual score relative to all of the other scores in the set.

Front 4

Frequency distribution must be presented with these two elements

Back 4

1. the set of categories that make up the original measurement scale

2. a record of the frequency,or number of individuals in each category

Front 5

Ordinal, interval and ratio scales list their data values from

Back 5

highest to lowest

Front 6

Define Proportion

Back 6

measures the fraction of the total group that is associated with each score

Front 7

What is the equation for proportion

Back 7

P=(f/N)

P: proportion

f: frequency

N: number

aka relative frequencies

Front 8

what is the equation for percentage

Back 8

p(100) =P=(f/N)(100)

P: proportion

f: frequency

N: number

Front 9

Define grouped frequency distribution table

Back 9

presenting the data in a series of class interval groups

Front 10

Guidelines for construction of a grouped frequency distribution table

Back 10

1) group the intervals abt 10 apart depending on the size of the data.

2) Width: number you can easily could up with (2,5,10,20 etc. )

3) bottom score multiple of the width

4) all intervals same width

Front 11

Define apparent limits

Back 11

appears that they form the upper and lower boundaries for the class interval

Front 12

Example of an apparent limit

Class interval 30-40 what are the apparent limits

Back 12

lower bound: 29.5
upper bound: 40.5

Front 13

Define histogram and order

Back 13

1. label height of the bar corresponds to the frequency for that category.

2/ for continuous variable, the width of the bar extends to the real limits of the category `

Front 14

Steps to create a polygon

Back 14

1. dot centered above each score so that the vertical position of the dot corresponds to the frequency for the category

2. line drawn dot to dot

3. completed by drawling line from 0 to 1st data point and so on and then end at 0 again

Front 15

What two types of graph can document class intervals

Back 15

histogram and polygram

Front 16

Define Bar graphs

Back 16

same as histogram but with spaces between the data. Emphasis that the data is different

Front 17

What do graphs usually contain

Back 17

relative frequencies and smooth curves

Front 18

Define relative frequencies

Back 18

no concrete number but estimation that something is 2x or 3x etc bigger or small than something else.

Front 19

3 characteristics to describe distribution

Back 19

Shape, central tendency and variability.

Front 20

Define central tendeny

Back 20

measures where the center of the distribution is located

Front 21

Define variability

Back 21

tells whether the scores are spread over a wide range or are clustered together

Front 22

Define symmetrical distribution

Back 22

able to draw a vertical line thought the middle so that one side of the distribution is mirror image of the other.

Front 23

Define skewed distribution

Back 23

the scores tend to pile up toward one end of the scale and taper off gradually at the other end.

Front 24

Define positively skewed distribution

Back 24

a skewed distribution with the tail on the right hand side

Front 25

Define negatively skewed distribution

Back 25

a skewed distribution with the tail on the left hand side

Front 26

Define descriptive statistics

Back 26

summarize, organize, and simplify data (sos)

Front 27

What are the graphic forms of descriptive statistis

Back 27

frequency distribution tables

grouped frequency distribution tables

histograms

bar graphs

polygons

Front 28

Define frequency distribution tables

Back 28

organized tabulation of the number of individual scores located in each category on the scale of measurement

Front 29

advantages of frequency distribution tables

Back 29

organized picture of the entire set of score

allows you to see the location of any individual score relative to all of the other scores in the set

Front 30

Frequency distribution tables list their values from _______ to ________

Back 30

highest to lowest

Front 31

What are some examples use GFDT ( grouped frequency distribution tables)

Back 31

exams scores

Front 32

Steps for creating grouped distributions

Back 32

1. determine range

2. divide the range by ___ with to get 10 intervals

3. determine the intervals ( same width, hightest/ lowest number accounted)

Front 33

Advantages and disadvantages of tables

Back 33

Advantage: concise presentation of all the data

Disadvantages: limit the detection of: relationship between variables, overall trends in the data, primary characteristics of the data

Front 34

2 rules for frequency distribution graphs

Back 34

1. point where two axes intersect should have a value of zero for both scores and their frequencies.

2. Height should be approximately 2/3rds to 3/4 the length

Front 35

What are the 3 types of frequency distribution graphs

Back 35

histogram, bar graph, polygon

Front 36

Histograms are used with _____ and ______ scales

Back 36

interval and ratio

Front 37

Bar graphs are used with ____ and _______ scales

Back 37

nominal and ordinal scales

Front 38

A polygon is used with ___ and ______ scales and must always ______ and ______ at zero

Back 38

interval

ratio

start

end

Front 39

3 characteristics that describe distributions

Back 39

1. Shape_ symmetrical vs. skewed

2. central tendency

3. variability

Front 40

Define symmetrical shapes of distribution

Back 40

halves are mirror images (normal distribution)

Front 41

Define central tendency

Back 41

a statistical measure to determine a single score that defines the enter of a distribution

Front 42

3 measures of central tendency

Back 42

mean, median, mode

Front 43

Symbols for sample mean is ______ where as the symbol for population mean is ________

Back 43

M

u(MYOO)

Front 44

Equations of population mean

and sample mean

Back 44

population mean (myoo)= sum(x) /N

sample mean M= sum (x)/n

N/n = number of score

Front 45

What is the equation for weighted mean

Back 45

( sum of x1+sum of x2)/(n1+n2)

Front 46

will changing a single score or adding/ subtraccting a new score change the mean?

Back 46

YESSS!

EXCEPT: when the new score equals the mean

Front 47

is there a symbol for median?

Back 47

no!!

Front 48

define median split

Back 48

gives researchers two groups of equal sizes, low scorers and high scorers

Front 49

When do you use the median

Back 49

extreme scores/ skewed distributions

undetermined values(if someone doesnt finish a race)

open ended distributions: no upper limit or lower limit for a category (5+ children, cannot compute the sum of x

Front 50

The ___ is located in the middle of the distribution_ in terms of the distances of the scores from the middle

Back 50

Mean

Front 51

The _______ is located in the middle of the distribution--- in terms of the number of scores aboce and below the middle

Back 51

median

Front 52

The _______ can be considered the _______ for a distribution because the distance of the scores above the mean are equal to the distances of the scores below the mean

Back 52

Mean

balance point

Front 53

does the mode have a symbol?

Back 53

no!

Front 54

What is bimodal?

Back 54

two modes/ peaks these can bee equal or major/ minor

Front 55

Define multimodal

Back 55

more than two modes

Front 56

When to use mode?

Back 56

1.with nominal scales(measure of central tendency)

2.discrete variables: what is the most typical

3.Describing shape: gives indication of the shape of distribution

Front 57

In a normal and symmetrical distribution the mean median and mode are _______

Back 57

the same

Front 58

In an symmetrical non normal distribution the ____ and _____ is the ______ but the ______ is different

Back 58

Mean and median, same but the mode

Front 59

General rules for skewed data

Back 59

1. the median is always in between the mode and the mean

2. mode is always the peak