DSILYTC Lecture 1 (01/16/25) PDF
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This document introduces the fundamental concepts of statistics, including the purpose, branches (descriptive and inferential), and types of variables. It defines key terms like population, sample, census, survey, parameter, and statistic. It also explains the four scales of measurement: nominal, ordinal, interval, and ratio.
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DSILYTC LECTURE 1 (01/16/25) Introduction and Terminologies Purpose of Statistics - To provide information - To provide comparison - To help discern relationships ; relationship of variables ; get a specific index of relationships...
DSILYTC LECTURE 1 (01/16/25) Introduction and Terminologies Purpose of Statistics - To provide information - To provide comparison - To help discern relationships ; relationship of variables ; get a specific index of relationships - To aid in decision making - To justify claims or assertions - To estimate unknown quantities - To predict future outcomes Statistics: A science that deals with collection, organization, presentation, analysis and interpretation of data. Analysis - extracting important information from the data which helps interpret the result When you interpret, make a decision and think of a recommendation Two Phases / Branches (1) Descriptive Statistics: collection, organization, summarization, and presentation of data (2) Inferential Statistics: making predictions or inferences about an entire population based on information provided by the sample Population: consists of the totality of all the elements or entities from which you want to obtain an information Sample: subset of the population Census: process of collecting information from the entire population; done by government offices; PSA Survey: process of collecting information from the sample Parameter: summary or numerical measure to describe a population Mean Median Mode Statistic: summary or numerical measure used to describe a sample Constant: character or property of a population or sample which makes the members similar to each other Variables: any characteristics or information measurable or observable on every element of the population or sample Qualitative (categorical): indicate what kind or what type Quantitative (numerical): how much or how many - Discrete: whose values are obtained through the process of counting - Continuous: obtained through the process of measuring Dependent: affected by another variable Independent: affects dependent variable Scales of Measurement of Variables (1) Nominal: lowest level of measurement known as categorical scale; simply labels or names or categories without any explicit or implicit ordering of the labels (2) Ordinal: names, labels, or categories with an implied ordering; ranking can be done on the data; distance between two labels cannot be determined because they are qualitative / categorical (3) Interval: values can be ordered, and distance between two labels are of known size; always numeric and have no true zero point (true value) ; must be interpreted using manual operation (4) Ratio: Highest level of measurement; has a true zero point; values have all the properties of the interval scale and the ratio of two values is meaningful
