Regeer

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  • Topic: Frequency distribution, Histogram, Data analysis
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  • Published : December 18, 2012
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CHAPTER TWO

DESCRIPTIVE STATISTICS:
TABULAR AND GRAPHICAL METHODS

CHAPTER OUTLINE AND REVIEW

In Chapter 1, you were introduced to the concept of statistics and in exercise *6 of that chapter you were given a frequency distribution of the ages of 180 students at a local college, but you were not told how this frequency distribution was formulated. In Chapter 2 of your text, you were informed how such frequency distributions could be formulated and were introduced to several tabular and graphical procedures for summarizing data. Furthermore, you were shown how crosstabulations and scatter diagrams can be used to summarize data for two variables simultaneously. The terms that you should have learned from this chapter include:

A.Qualitative Data:Data that are measured by either nominal or ordinal scales of measurement. Each value serves as a name or label for identifying an item.

B.Quantitative Data:Data that are measured by interval or ratio scales of measurement. Quantitative data are numerical values on which mathematical operations can be performed.

C.Bar Graph:A graphical method of presenting qualitative data that have been summarized in a frequency distribution or a relative frequency distribution.

D.Pie Chart:A graphical device for presenting qualitative data by subdividing a circle into sectors that correspond to the relative frequency of each class.

E.FrequencyA tabular presentation of data, which shows the Distribution:frequency of the appearance of data elements in several nonoverlapping classes. The purpose of the frequency distribution is to organize masses of data elements into smaller and more manageable groups. The frequency distribution can present both qualitative and quantitative data.

F.Relative FrequencyA tabular presentation of a set of data which shows Distribution:the frequency of each class as a fraction of the total frequency. The relative frequency distribution can present both qualitative and quantitative data.

G.Percent FrequencyA tabular presentation of a set of data which shows Distribution:the percentage of the total number of items in each class. The percent frequency of a class is simply the relative frequency multiplied by 100.

H.Class:A grouping of data elements in order to develop a frequency distribution.

I.Class Width:The length of the class interval. Each class has two limits. The lowest value is referred to as the lower class limit, and the highest value is the upper class limit. The difference between the upper and the lower class limits represents the class width.

J.Class Midpoint:The point in each class that is halfway between the lower and the upper class limits.

K.CumulativeA tabular presentation of a set of quantitative data
Frequencywhich shows for each class the total number of data
Distribution:elements with values less than the upper class limit.

L.Cumulative RelativeA tabular presentation of a set of quantitative data
Frequencywhich shows for each class the fraction of the total Distribution:frequency with values less than the upper class limit.

M.Cumulative PercentA tabular presentation of a set of quantitative data
Frequencywhich shows for each class the fraction of the total Distribution:frequency with values less than the upper class limit.

N.Dot Plot:A graphical presentation of data, where the horizontal axis shows the range of data values and each observation is plotted as a dot above the axis. O.Histogram:A graphical method of presenting a frequency or a relative frequency distribution.

P.Ogive:A graphical method of presenting a cumulative frequency distribution or a cumulative relative frequency distribution.

Q.Exploratory DataThe use of simple arithmetic and easy-to-draw
Analysis:pictures to...
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