Chapter 2: Organizing & Summarizing Data Flashcards
What is a (Distribution)?
Data from a data set aligned from lowest to highest.
What are the 2 ways to display data?
Using a graph or a numerical table.
What is a (Frequency Distribution)?
A table that shows how often each class of data occurs in a data set.
What is the (Frequency) of a piece of data?
The frequency in a data set is the number of times that particular class of data occurs.
What is (Relative Frequency)?
Class frequency divided by total in data set, from this we can make a graph showing which type of data occurs most frequently.
What is a (Class)?
A group, set, category of things that share common attributes, used for qualitative data.
What is a (Class Width)?
The difference between two consecutive lower or upper class limits
What is a (Class Frequency)?
The number of times a piece of data, from a data set appears in a particular class.
How do you determine (Class Size)?
Take two consecutive lower end ranges of classes and subtract the difference is the class size, eg 2 classes of between 40-25, & 20-50, take 40-20=20, thus the class size is (20).
What is (The Central Tendency), & what does it consist of, describe each tendency?
The (Central Tendency) is a single value that best describes a data set, thus a large amount of info. is condensed into a single number, (CT) consist of the (Mean, Median, Midrange, & Mode)
1) Mean: Most used of the tendencies, scores are added, then divided by number of scores, should not be used for (Nominal Data), & can be effected by extreme scores.
2) Median: Score found in the middle of scores ranked from lowest to highest, median is not effected by extreme scores.
3) Midrange: Highest & lowest scores are added, & divided by 2.
4) Mode: Score that occurs most often, used most for (Nominal Data), least used of the tendencies.
Describe the elements of a (Bar Graph)?
Each individual piece of data is described on the X axis of the bar graph, depending on what is asked the frequency or relative frequency is located on the Y axis, the height of each rectangle assigned for each piece of data is the same as the frequency or relative frequency on the Y axis.
What is the purpose of a (Side-by-Side Bar Graph)?
It’s use to compare, or contrast two separate sets of data, eg. compare or contrast frequency or relative frequency of events that happened in two separate years, to distinguish the difference each year is represented by a different color.
What method of measuring is best for (Qualitative Variables) and (Quantitative Variables)?
For (Qualitative) variables the best methods are pie charts, bar graphs, or tables, for (Quantitative) variables the best methods are dot plots, stem and leaf displays, & histograms.
What are the advantages and disadvantages of the (Stem and Leaf Display vs the Histogram)?
Stem and leaf display is not good for large amounts of data, vs the histogram which shows large amounts of data well, if data is large enough the histogram will look like a smooth curve.
The histogram cannot tell us the frequency of a piece of data from a data set like the stem and leaf display can.
What is a (Histogram), & what type of data is it usually used with?
A graph that consists of rectangles for each class of data, & are found on the X axis, the height of the rectangles correspond to the frequency, or relative frequency found on the Y axis, best used when describing (Quantitative Data).
