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UNR, MATH/STAT 352, Spring 2007
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MATH/STAT 352: Quiz 0
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A subset of the data from a study of a series of male patients from Greenlane Hospital in Aukland after a heart attack Goal of the study: How long will the patient live after the heart attack? UNR, MATH/STAT 352, Spring 2007
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(Age, time, probability, etc.) (Color, surgery outcome, smoking, etc.) May take any value from some interval (probability) No order (surgery outcome) May take values from some grid (age in years) Order (Letter grade) UNR, MATH/STAT 352, Spring 2007
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is determined by data you have and problem you consider Aging of a person is a continuous process Age is a quantitative, continuous variable Age in years (18, 25, 63,…) is quantitative, discrete Age as (Kid, Young, Middle-age, Senior) is qualitative, ordinal Time
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A subset of the data from a study of a series of male patients from Greenlane Hospital in Aukland after a heart attack Goal of the study: How long will the patient live after the heart attack? UNR, MATH/STAT 352, Spring 2007
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Original data: {8 3 6 4.5 4 4.5} Sorted data: {3 4 4.5 4.5 6 8} Simple graph: dot plot UNR, MATH/STAT 352, Spring 2007
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Interesting features of the data emphasized by the dot plot UNR, MATH/STAT 352, Spring 2007
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Exploiting gaps and clusters: UNR, MATH/STAT 352, Spring 2007
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Data from Quiz 0 outliers body of data
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Measurement Histogram is the most widely used statistical graph UNR, MATH/STAT 352, Spring 2007
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Divide observational interval into subintervals, (also called bins, class intervals) Measurement Calculate number of observation within each bin n1n1 n2n2 n3n3 n4n4 n5n5 n6n6 n7n7 n8n8 n9n9 n 10 Draw a rectangle w/heigth = number of observations = frequency Relative frequency is the number of observations within a bin divided by the total number of observations UNR, MATH/STAT 352, Spring 2007
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Measurement 12343124 Number of observations Measurement.05.1.15.2.15.05.1.2 Fraction of observations n=20 (sample size) k=8 (# of bins) n=20 (sample size) k=8 (# of bins) UNR, MATH/STAT 352, Spring 2007
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080 – right answer Data from Quiz 0
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UNR, MATH/STAT 352, Spring 2007
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UCLA, Stats 14, Fall 2004 UNR, MATH/STAT 352, Spring 2007
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Data from Quiz 0
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UNR, MATH/STAT 352, Spring 2007 Data from Quiz 0
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UNR, MATH/STAT 352, Spring 2007 Data from Quiz 0
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UNR, MATH/STAT 352, Spring 2007 Data from Quiz 0
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UNR, MATH/STAT 352, Spring 2007 Data from Quiz 0
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UNR, MATH/STAT 352, Spring 2007 WRB number Data from Quiz 0
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UNR, MATH/STAT 352, Spring 2007 http://static.deliaonline.com/images/originals/cc444-apple-blackberry-pie-18775.jpg
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UNR, MATH/STAT 352, Spring 2007
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Central values and spread Measurement x 0 is the central value, characteristic value spread, most of the observed values UNR, MATH/STAT 352, Spring 2007
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Definitions: A population is the entire collection of objects or outcomes about which information is sought. A sample is a subset of a population, containing the objects or outcomes that are actually observed. A simple random sample (SRS) of size n is a sample chosen by a method in which each collection of n population items is equally likely to comprise the sample, just as in the lottery.
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UNR, MATH/STAT 352, Spring 2007 Definition: A sample of convenience is a sample that is not drawn by a well-defined random method. Things to consider with convenience samples: Differ systematically in some way from the population. Only use when it is not feasible to draw a random sample.
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UNR, MATH/STAT 352, Spring 2007 A SRS is not guaranteed to reflect the population perfectly. SRS’s always differ in some ways from each other; occasionally a sample is substantially different from the population. Two different samples from the same population will vary from each other as well. This phenomenon is known as sampling variation.
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UNR, MATH/STAT 352, Spring 2007 Definitions: A tangible population is a finite population that consists of actual objects. Examples: People in our class, buildings in Reno. A conceptual population consists of items that are not actual objects. Examples: All possible shootings from the riffle, all possible tossings of a coin, all possible results of weighting a rock sample.
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