Privitera chapter 2

Why are relative frequency reported we percents

Easier to read than decimals

Cumulative frequencies can be added from the top ___ and bottom ___

Down, up

Summary display for a distribution of data organized or summarized in terms of how often ( or frequently) scores occur

Frequency distribution

Histograms summarize

Frequency of continuous data that is quantitative

bar chart

Graphical display used to summarize frequency of discrete and categorical data distributed in whole units or classes

Grouped data often summarized graphically using

Histogram

Problems with open intervals

Make it difficult to identify if outliers exist in data set

Difference between histogram and stem and leaf

Stem and leaf display actual scores and histogram lists frequencies

cumulative frequency

Sum of scores across each range and always sums to the total number of scores in a distribution

A cumulative percent distribution is

Summary display that distributes sum of relative percents across series of intervals

Relative frequency =

frequency/sum of all frequencies

frequency polygon

graph of a frequency distribution that shows the number of instances of obtained scores, usually with the data points connect by straight lines. Dot and line graph plotted at midpoint of each interval

Real range

one more than the difference between the largest and smallest value in a data set

rules for a simple frequency distribution

-each interval is defined -each interval is equidistant -no interval overlaps -all values are rounded to same degree of accuracy measured in original data

How to identity rank of individual

1- identify interval within which a specified point falls 2- identify real range for interval identified 3- find position of percentile point within the interval , multiply fraction by width of real range 4- identify percentile point

3 rules of histograms

1- vertical rectangle reps each interval and height equals frequency 2- base of es rectangle behind and ends at upper and lower boundaries or each interval 3- each rectangle touches adjacent rectangles at boundaries of each interval

Sum of all proportions for a distribution

1.0

Relative percent sums to

100%

What is the recommended number of intervals that should be included in a simple frequency distribution

5-20 intervals

Ogive

A line graph that depicts cumulative frequencies. Dot and lime graph plotted at upper boundary of each interval

stem and leaf plot

A method of graphing a collection of numbers by placing the "stem" digits (or initial digits) in one column and the "leaf" digits (or remaining digits) out to the right.

When cumulative frequencies from bottom up you typically want to discuss data in terms of

At most, less than, at or below

When comulating frequencies grim the top down you want to discuss data in terms of

At or above

Similar to histogram except bars seperated from one another

Bar chart

degree of accuracy

Being free from errors within a specified tolerance.

summary display that distributes the sum of frequencies across a series of intervals

Cumulative frequency

Ogive typically summarized what type of frequency distribution

Cumulative percent distribution

Proportion is

Part of portion of all measured data

Used to effectively summarize frequency data

Pictures and pictographs

Summary display that distributes the proportion of scores in each interval. It's computed as frequency increases each interval divided by total number of frequencies recorded

Relative frequency

Ungrouped data can be summarized using

Relative frequency, relative percent, cumulative relative frequency, relative percent and cumulative relative percent

Summary display that distributes the percentage of scores occurring in each interval relative to all scores distributed

Relative percent distribution

bottom-up frequency

Start with lowest at bottom top is sum of all

When would a researcher construct a relative frequency table

To summarize large data sets

True or false whether you consulate a frequency distribution from bottom up or top down depends on how you wanna discuss data

True

When dependent variable is qualitative or categorical or number of different scores is small data is then

Ungrouped, intervals not constructed

Percentile point is

Value of a score on a measurement scale below which a specified percentage of scores in a distribution fall

percentile rank

the percentage of scores below a specific score in a distribution of scores

interval width

the range of values contained in each interval of a grouped frequency distribution. Real range divided by number of intervals