Qu1 Chapter 2: Presenting data in tables and charts - NOtes Flashcards
How do you organize numerical data
- the ordered array 2. the stem-and-leaf display
What is the ordered array
ordered sequence of raw data, in rank order from the smallest observation to the largest - makes it easy to pick out extremes, typical values and the area where the majority of the values are concentrated
What is a stem and leaf display
valuable tool for organizing a set of data and understanding how the values distribute and cluster over the range of the observations in the data set
it separates data enteries itno leading digits, or stems adn trailing digitis or leaves
First column of numbers is the stem, or leading digitis
the leaves or trailing digits, branch out to the righ to the right of these numbers
What is raw form
as collected
24,26,24,21,27,27,30,41,32,38
What is frequency distribution
a summary table in which the data are arranged into conveniently established, numerically ordered class groupings or categories
its a table that displays the frequency of various outcomes in a sample
each entry in the table contains the frequency or count of th eoccurences of values within a particular group or interval, and in this way, the table summarizes the distribution of values in the sample.
What is frequency Distribution
summary table in which the data are arranged into class groupings or categories
Describe Frequency Distributions
- sort raw data in ascending order
12,13,17,21,24,24,26,27,27,30,32,35,37,38,41,43,44,46,53,58
- Find range: 58 -12 = 46
- select number of classes : 5 (usually between 5 and 15)
- compute class interval (width) 1o (46/5 then round up)
- determine class boundaries (limits): 10,20, 30, 40, 50, 60
- Compute class midpoints: 15, 25, 35, 45, 55
- Couny observations and assign to classes
The histogram
to enhance the analysis of a frequency distribution we can use what?
- relative frequency distribution (proporiton) or
- precentage distribution
What is the formula for relative frequency distriution
frequencies in each class of the frequcency distribution / total number of observations
what is the formual for percentage distribution
multiply each relative frequency or portion by 100
what is the cumulative distribution
a table of cumulative precentages
- useful technique for tabulating dta
- describes the probability that a real0valued ramdon varaivel x with a given probability distirubiton will be found to have a avlue less than or equal to x.
describe the histogram
a chart in which the rectangular bars are constructed at the boundaries of each class “ a picture is worht a 1000 words”
need more
what is the polygon
- the percentage polygon is forme dby having the midpoint of each class represent the data in that class and then connecting the sequence of midpoints at their respective class precentages
- when plotting the variables of interst is displayed along the horizontal axis
- the verticle axis represents the number, proportion, or precentage of observations per class interval
what is the cumulative polygon (Ogive)
- a graphical represnation of a cumulativ eprecentage distribvution
when plotting cumulative poloygons
- the variable of interest is displayed along the x-axis - the y-axis represnts the percentages of cumulated observations
What is Bivariate numerical data
data relating to tow numerical varialbes
for example, height and weight
- use scatter diagram
What are the tables and charts for Categorical Data?
- Summary Table
- The Bar Chart
- Pie Chart
- Pareto Diagram