# Ch-1-3502 - Note all deﬁnitions are from your textbook CHAPTER 1 z What is Statistics The discipline of statistics teaches us how to make

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Unformatted text preview: Note: all deﬁnitions are from your textbook CHAPTER 1 z What is Statistics? The discipline of statistics teaches us how to make intelligent judgments and informed deci-sion in the presence of uncertainty and variation. ± Branches of Statistics • Descriptive Statistics: Collecting data, summarizing and describing the important features of the data. Methods: – Graphical * Steam and leaf * Histogram * Boxplot * Scatterplot – Numerical Summary Measures * Mean * Median * Variance * Standard deviation • Inferential Statistics: Generalized the results from a sample to a population. Methods: – Point estimation – Conﬁdence interval – Hypothesis testing 1 F Some Deﬁnitions • Population is a collection of all objects. • Sample is a subset of population. • Variable is any characteristic whose value may change from one object to another in the population. • Experimental unit is the individual or object on which a variable is measured – Discrete variable is almost always result from counting and its possible values are 0,1,2,. ... or some subset of these digits. – Continuous variable is possible values consists of an entire interval on the number line and arises from making measurements. • Univariate data result consists of observations on single variable. • Bivariate data arises when observations are made on each of two variables. • Multivariate data arises when observations are made on more than two variables. ± Collecting Data Try to develop the techniques for collecting the data. Simplest method is Simple Random Sampling , in this method any particular subset of the speciﬁed size (e.g., n = 100) has the same chance of being selected. F Visual Techniques ± Stem and leaf Steps for Constructing a Stem and Leaf Plot – Select one or more leading digits for the stem values. The trailing digits become the leaves. – List possible stem values in a vertical column. – Record the leaf for every observation beside the corresponding stem value. – Indicate the units for stems and leaves someplace in the display. 2 ± Histogram Constructing a Histogram for Discrete Data First, determine the frequency or relative frequency of each X value. Then mark pos-sible X values on a horizontal scale, above each value draw a rectangle whose height is the frequency or relative frequency of that value....
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## This note was uploaded on 09/27/2010 for the course STAT 104157 taught by Professor Jhonbran during the Spring '09 term at California Coast University.

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Ch-1-3502 - Note all deﬁnitions are from your textbook CHAPTER 1 z What is Statistics The discipline of statistics teaches us how to make

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