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Quantitative Analysis: Basics Sebastian M. Rasinger Quantitative Research in Linguistics. An Introduction 2 nd edition. 2013. London: Bloomsbury S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Agenda Statistics – what for? Quantitative data – what, how, why? Descriptive statistics –frequencies –Measures of location –Measures of dispersion Relationships between variables S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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What is statistics? Any orderly summary of numbers, e.g. results of an election, league table etc Numerical measurement describing some characteristic of a sample Collection of methodological tools which help to systematically and exemplarily collect, process and display information, e.g. inflation rate, unemployment rate S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Statistics as a basis for decisions Numerous possibilities to process an issue statistically problem of measurement Different interpretation of results: glass half empty or half full? Manipulation of raw data S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Statistics: 3 purposes Description: –Quantifying and summarising information in order to describe and display an issue in the most effective and optimal manner: tables, graphs, main statistical values –Aim: describing the reality S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Statistics: 3 purposes (cont’d) Generalisation: –Inference: inferring information about the population via a small sample Population sample S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Statistics: 3 purposes (cont’d) Identification of causal relationships, i.e. how two (or more) phenomena are related e.g. effect of learner’s age on language attainment S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Quant. Data: discrete or continuous Discrete: finite or countable number of possible values –E.g. numbers of students in a class (there’re no half students…) Continuous: infinitely many possible values on a continuous scale without gaps/interruptions –E.g. amount of coffee a university lecturer drinks a day: continuous (e.g. 1.256 litres) S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Levels of measurement Nominal data: –names, labels, categories. Cannot be arranged in high/low scheme, e.g. sex Ordinal data: –Data may be arranged in some order, but differences between value cannot be determined or are meaningless, –e.g. ‘good’ – ‘average’ – ‘poor’ rankings S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Levels of measurement (2) Interval data: –meaningful difference between data, but no natural zero starting point for when no quantity is present, e.g. Fahrenheit: 0° doesn’t mean no heat Ratio data: –Natural zero point, e.g. length of lecture in minutes: 0 minutes = no lecture S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Absolute and Relative frequency Students on a year 1 UG course achieved the following results in an exam 1st class4 Upper Second Class8 Lower Second Class11 Third Class3 Fail1 Absolute frequency S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Absolute & Relative frequency (2) Relative frequency: Where n is the total number of items/observations in a sample S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Relative frequency Abs.Rel.% 1st class40.148114.81 Upper Second Class80.296329.63 Lower Second Class110.407440.74 Third Class30.111111.11 fail10.0373.7 271100 Percentage: relative frequency x 100 S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Summarizing data: classes and class width The following table shows the number of students for 20 courses over the last year No obvious classes. Useless information. 1.Determine number of non-overlapping classes 2.Determine the width of each class 3.Determine the class limits 1214191815 18172027 22232221332814181613 S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Classes and class width 1.20 observations 5 classes reasonable 2.Width of classes 3.Class limits Lower limit: smallest possible value in a class Upper limit: largest possible value in a class Number of classes, width and limits depend on researcher’s judgement S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Classes and class width (cont’d) Class intervalsFrequencyRelative frequency 10-1440.20 15-1980.40 20-2450.25 25-2920.10 30-3410.05 Total201 S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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Cumulative frequencies Running total of frequencies through all classes Class intervalsfRf cfcRf 10-1440.2040.20 15-1980.40120.60 20-2450.25170.85 25-2920.10190.95 30-3410.05201 Total201 S.M.Rasinger. 2013. Quantitative Research in Linguistics. 2e. Bloomsbury.
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