Introduction to Statistics (PDF)

UNIT 1 OBJECTIVES Define Statistics Differentiate a sample from a population; inferential from descriptive statistics Distinguish a parameter from a statistic Differentiate qualitative data fr...

UNIT 1 OBJECTIVES Define Statistics Differentiate a sample from a population; inferential from descriptive statistics Distinguish a parameter from a statistic Differentiate qualitative data from quantitative data OBJECTIVES Contrast a discrete from a continuous data Give examples of nominal, ordinal, interval, and ratio data State the uses of Statistics INTRODUCTION Examples of Statistics Current events with statistics (local/international ) 1. 2. 3.  MEANING OF STATISTICS Statistics – the science of collecting, organizing, presenting, analyzing, and interpreting data to assist in making effective decisions  HISTORY OF STATISTICS AD 2: Evidence of a census completed during the Han Dynasty survives. 1500s: Girolamo Cardano calculates probabilities of different dice rolls. 1600s: Edmund Halley relates death rate to age and develops mortality tables. 1700s: Thomas Jefferson directs the first U.S. Census.  HISTORY OF STATISTICS 1839: The American Statistical Association is formed. 1894: The term “standard deviation” is introduced by Karl Pearson. 1935: R.A. Fisher publishes Design of Experiments.  HISTORY OF STATISTICS Sir Ronald Fisher Touted as the greatest scientist of his time, Sir Ronald Fisher (1890- 1962) was a British statistician and biologist who was known for his contributions to experimental design and population genetics. He is known as the father of modern statistics and experimental design.  USES OF STATISTICS (1) Statistics helps in providing a better understanding and exact description of a phenomenon of nature. (2) Statistics helps in the proper and efficient planning of a statistical inquiry in any field of study. (3) Statistics helps in collecting appropriate quantitative data. (4) Statistics helps in presenting complex data in a suitable tabular, diagrammatic and graphic form for easy and clear comprehension of the data.  USES OF STATISTICS (5) Statistics helps in understanding the nature and pattern of variability of a phenomenon through quantitative observations. (6) Statistics helps in drawing valid inferences, along with a measure of their reliability about the population parameters from the sample data.  USES OF STATISTICS Business Statistics plays an important role in business. A successful businessman must be very quick and accurate in decision making. He knows what his customers want; he should therefore know what to produce and sell and in what quantities. Economics Economics largely depends upon statistics. National income accounts are multipurpose indicators for economists and administrators, and statistical methods are used to prepare these accounts.  USES OF STATISTICS Mathematics Statistics helps in describing these measurements more precisely. A large number of statistical methods like probability averages, dispersions, estimation, etc., is used in mathematics Banking Banks make use of statistics for a number of purposes. Bankers use statistical approaches based on probability to estimate the number of deposits and their claims for a certain day.  USES OF STATISTICS State Management (Administration) Statistics is essential to a country. Different governmental policies are based on statistics. Statistical data are now widely used in making all administrative decisions.. Accounting and Auditing Accounting is impossible without exactness.. The correction of the values of current assets is made on the basis of the purchasing power of money or its current value.  USES OF STATISTICS Natural and Social Sciences Statistical methods are commonly used for analyzing experiments results, and testing their significance in biology, physics, chemistry, mathematics, meteorology, research, chambers of commerce, sociology, business, public administration, communications and information technology, etc. Astronomy Astronomy is one of the oldest branches of statistical study; it deals with the measurement of distance, and sizes, masses and densities of heavenly bodies by means of observations. USES OF STATISTICS STEPS IN STATISTICAL INQUIRY STRUCTURE OF STATISTICAL INQUIRY STRUCTURE OF STATISTICAL INQUIRY STRUCTURE OF STATISTICAL INQUIRY ELEMENTS OF STATISTICS  CLASSIFICATION OF VARIABLES Variable – observable characteristic of a population or a sample A qualitative variable is nonnumeric, often summarized in charts and bar graphs A quantitative variable is a variable that can be reported numerically - Discrete variable can assume only a certain value, and there are “gaps” between the values - Continuous variable can assume any value within a specific range LEVELS OF MEASUREMENT  SHORT ACTIVITY Place these variables in the following classification tables. For each table, summarize your observations and evaluate if the results are generally true. For example, salary is reported as a continuous quantitative variable. It is also a continuous ratio scaled variable. Use letters only. a Strokes in d Children in g TV sets a golf hole the family owned b Amt. of e Weight of a h Yearly rainfall income tax student in Baguio City paid c Brand of f Marital status i Hair color PC  SHORT ACTIVITY a Strokes in d Children in g TV sets a golf hole the family owned b Amt. of e Weight of a h Yearly rainfall income tax student in Baguio City paid c Brand of f Marital status i Hair color PC Discrete variable Continuous variable qualitative quantitative  SHORT ACTIVITY a Strokes in d Children in g TV sets a golf hole the family owned b Amt. of e Weight of a h Yearly rainfall income tax student in Baguio City paid c Brand of f Marital status i Hair color PC Discrete variable Continuous variable nominal ordinal interval ratio  RAW DATA and ARRAY Raw Data – data in its original form Array – data arranged either from highest to lowest or from lowest to highest Raw Data 23, 34, 45,23, 27,30,50,45,47, 19 Array 19, 23,23, 27, 30,34, 45,45,47,50 QUESTIONS WHAT HAVE I LEARNED TODAY? QUESTIONS