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The nature of statistics. - Introduction Definition of “statics” 1-facts or data of a numerical kind, assembled ,classified and tabulated so as to present Sign if I cant in formation about a given subject
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The nature of statistics -Introduction Definition of “statics” 1-facts or data of a numerical kind, assembled ,classified and tabulated so as to present Sign if I cant in formation about a given subject 2-technically : statistics means more than this . Not only do statisticians assemble, classify And tabulate data ,but than also analyze data in order to make generalizations and Decisions . For example ,a portion analyst can use data from a portion of the voting population to Predict the political preferences of the entire voting population
1.1: two kinds of statistics : Def.1.1 descriptive statistics : Consists of methods for organizing and summarizing information in clear and effective way. Descriptive statistics includes construction of graphs ,charts and tables , and the calculation Of various descriptive measures , such as averages and percentiles For example 1.3 The study table 1.1 gives the voting results for 1948 presidential election this study is descriptive . It is a summary of the votes cast by the entire population of voters.
def.1.3.inferential statistics consists of methods of drawing conclusions about a population based on information ,obtained from a sample of the population Ex.1.2. in the fall of 1948 , president Truman was concerned about statistics the Gallup poll before the election predicted that he would win only 44. 5 % of the vote and be defeated by the republican nominee , Thomas e. Dewey . This time however the statisticians had predicted incorrectly . Truman won more than 49 % of the vote ,and with it the presidency . The Gallup organization modified some of its procedure and has correctly predicted the winner since
definition 1.2. population and sample population : The collection of all individuals or items under consideration in a statistical study Sample : The port of the population from which information is collected
chapter 2 : organizing data 2.1 Data The information collected , organized and analyzed by statisticians is called data • -Types of data : De.2.1 Qualitative data : data that give non –numerical information such as gender , aye color and blood type Metric data : data obtained from the measurement of quantities . Such as time , high and Wight . Ordinal data : data about order or rank on a scale such as l,2,3.. Or a,b,c,… de.(2.5) frequency data or (count data) : Data on the number of individuals or items falling in various categories . Ex.2.2: illustrates types of data – Ex.2.3. `` `` ``` ``` Ex.2.4 `` `` `` ``
Discrete and continuous data : Qualitative and ordinal data are refereed to as discrete , because they sort individuals or items into separate or discrete classes on the other hand , most metric data are called continuous since they involve measurement on a continuous scale . For example , the time that it takes a runner to complete a marathon can be any positive number .