Basic Statistics
Chapter 2: Summarizing Data in Tables and Graphs
Chapter 2: Summarizing Data in Tables and Graphs
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| Cartes-fiches | 24 |
|---|---|
| Langue | English |
| Catégorie | Mathématiques |
| Niveau | Université |
| Crée / Actualisé | 08.09.2015 / 08.09.2015 |
| Lien de web |
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Frequency Distribution
lists each category of data and the number of occurences for each category of data
Relative frequency
is the proportion (or percent) of observations within a category and is found using the formula
Relative frequency= frequency/sum of all frequencies
Relative frequency distribution
lists each category of data together with the relative frequency
Bar graph
is constructed by labeling each category of data on either the horizontal or vertical axis and the frequency or relative frequency of the category on the other axis. Rectangles of equal width are drawn for each category. The height of each rectangle represents the category's frequency or relative frequency.
Pareto chart
is a bar graph whose bars are drawn in deccreasing order of frequency or relative frequency.
Pie chart
is a circle divided into section. Each sector represents a category of data. The area of each sector is proportional to the frequency of the category.
histogram
is constructured by drawing by drawing rectangles for each class of data. The height of each rectangle is the frequency or relative frequency of the class. the width of each rectangle id the same and the rectangles touch each other.
lower class limit
the smallest value within the class
upper class limit
the largest calue within the class
Class width
the difference between consecutive lower class limits
Open ended
if first class has no lower class limit or the last class has no upper class limits.
Class width
class width= largest data value -smallest data value/ number of classes
Uniform Distribution
frequency of each value of the variable is evenly spread out across the values of the variable
Bell-shaped Distribution
highest frequency occurs in the middle and frequencies tail off to the left and right of middle.
Skewed Right
tail to right of peak is longer than the tail to the left of the peak
Skewed left
tail to left of peak is longer than the tail to the right of the peak.
Time-series data
when value of variable is measured at different points in tie
Time-Series Plot
obtained by plotting the time in which a variable is measured on the horizontal axis and the corresponding value of the variable on the vertical axis. Line segments are then drawn connecting the points.
Histogram
constructed by drawing rectangles for each class of data. The height of each rectangle is the frequency or relative frequency of the class. The width of each rectangle is the same and the rectangles touch each other.
Classes
categories into which data are grouped
Lower Class Limit
smallest value witin the class
Upper Class Limit
largest value within the class
Determining Class Width
1. Decide number of classes. Should be between 5-20 classes. Smaller the data set, fewer classes you should have
2. Compute class width
Largest data value- smallest Data Value/ # of classes.
Round value up to convenient number
Construction of Stem-and-Leaf Plot
Step1: Stem of a data value will consist of the digits to the left of the right most digit. The leaf of a data value will be the rightmost digit
Step 2: Write the stems in a vertical column in increasing order. Draw a vertical line to the right of the stems
Step 3: Write each leaf corresponding to the stems to the rigt of the vertcal line
Step 4: Within each stems, rearrange the leaves in ascending order, title the plot, and include a legend to indicate what the values represent.
