Qba Chapter 4

Front 1

Descriptive Statistics Organize Data for?

Back 1

-Show the general shape of the data
- Show where the values tend to concentrate
-Expose extreme or unusual data values

Front 2

Simple Random Sampling

Back 2

-a sample selected so that each item or person in the population has the same chance of being included
-most widely used type of sampling
-Ex. Place names in a box
- use a table of random numbers

Front 3

Systematic Random Sampling

Back 3

a random starting point is selected and then every kth member of the population is selected
-Used to sample from lists
Ex: Pulling from a hat
-Does not always satisfy definition of random sampling

Front 4

Stratified Random Sampling

Back 4

a population is divided into subgroups, called starta and a sample is randomly selected from each stratum
-Used when population can be clearly divided into groups
-Reflect the characteristics of a the population than a simple random sample

Front 5

Cluster Sampling

Back 5

-a population is divided into clusters using naturally occuring geographic or other boundaries. Clusters are then randomly selected and a sample is collected by randomly selecting from each cluster
-Used to reduce the cost of sampling when the population is scattered over a large geographic area
Ex: Different types of advertisers

Front 6

Frequency Table

Back 6

a grouping of qualitative data into mutually exclusive classes showing the number of observations in a class

Front 7

Equivalence Class

Back 7

a single value, a collection of values, or a qualitative category that is used to organize data into a logical fashion
-Some classes may contain no values

Front 8

Class Frequency

Back 8

Number of observations in each class

Front 9

Relative Frequency

Back 9

Fraction of the total number of observations in each class
-the sum of the relative frequencies is always 100 percent

Front 10

Bar Chart

Back 10

a. The height of each bar represents the frequency of a certain class

b. The horizontal axis is called the x-axis or abscissa

c. The vertical axis is called the y-axis or ordinate

d. The point at which the vertical axis and horizontal axis intercept is the origin

e. A space exists between the bars

Front 11

Ungrouped frequency table

Back 11

A frequency table where each of the class intervals is a single value
-Used for quantitative data

Front 12

Histogram

Back 12

-A graph of quantitative data in which the classes are marked on the horizontal axis and the class frequencies are marked on the vertical axis
- The class frequencies are represented by the heights of the bars
- The bars are drawn adjacent to each other
- Quantitative data can be continuous
- Adjacent bars show continuous nature of data
- Similar to a bar graph but used for quantitative data rather than qualitative data

Front 13

Difference between a Histogram and a Bar Chart

Back 13

Histogram:
-Used with quantitative data
-Bars touch

Bar graph:
- Used with qualitative data
-Bars do not touch

Front 14

Mesokurtic

Back 14

-Normal Distribution
-Bell Shaped Curve
-Symmetric

Front 15

Phtykertic

Back 15

-Flatter than normal distribution

Front 16

Lyptokurtic

Back 16

Skinner than normal distribution

Front 17

Negatively Skewed

Back 17

Mean < Medain

Front 18

Positively Skewed

Back 18

Median < Mean

Front 19

Bimodal

Back 19

Two Bumps

Front 20

Multimodal

Back 20

Three or more bumps

Front 21

J- Shaped

Back 21

increasing frequency at an increasing rate(no Hump)

Front 22

U Shaped

Back 22

increasing then decreasing frequency

Front 23

Rectangular

Back 23

each class interval has the same frequency

Front 24

Frequency Polygon

Back 24

- A graph of quantitative data in which line segments connect the points formed by the intersection of the class midpoints and relative class frequencies

- Error in book: Frequency polygons uses frequencies
- Frequency polygons are most commonly used with relative frequencies

Front 25

Cumulative Frequency Polygon

Back 25

- A graph of quantitative data in which the classes are marked on the horizontal axis and the cumulative relative frequencies are marked on the vertical axis

- If the cumulative frequency polygon is continuous than it is called an ogive