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Intro to statistics
- 1. INTRODUCTION TO STATISTICS RATHEESH R.L LECTURER MURLIDHAR COLLEGE OF NURSING
- 2. The word statistics comes from the Italian word statista and German word statistik. • The term was first used by professor Gottfried Achenwall in 1949.
- 3. DEFINITIONS • Statistics can be defined as numerical data involving variability and the treatment of such data. • Statistics can be defined as collection, presentation, analysis and interpretation of numerical data. croxton&cowden
- 4. • Statistics is the science of making effective use of numerical data which is related to collection, analysis and interpretation of data. • Statistics is the study of how to collect, organizes, analyze, and Interpret data.
- 5. BIOSTATISTICS • Biostatistics is the method used in dealing with statistics in the field of health sciences such as biology, medicine, nursing, public health, dentistry, pharmacy and physical therapy.
- 6. USE OF STATISTICS • It facilitate comparisons. • It help to answer important research questions and field in study. • It simplify the masses of figures • It helps to formulate or testing hypothesis. • It helps in prediction • To understand what tools are suitable for a particular research study.
- 7. TERMINOLOGY • DATA: It is a factual information collected during research study. • QUALITATIVE DATA: The variables that yield observations on which individuals can be categorized according certain characteristics or qualities are referred as Qualitative data. Eg: gender, occupation, marital status
- 8. • QUANTITATIVE DATA: The variables that yield observations that can be measured are considered quantitative data. Eg: height, weight, blood pressure • DISCRETE DATA: The data in a whole number is called discrete data. Eg: number of children in a family, pulse rate, ESR, blood sugar
- 9. • CONTINUOUS DATA: The data which can be measured in in fractional values. Eg: height, weight, body temperature
- 10. SCALES OF MEASUREMENTS • Measurement is the assignment of numbers to objects according to specific rules, to characterize quantities of an attribute. • It is a system of classifying measurements according to the nature of measurement and the type of mathematical operations to which they are amendable.
- 11. There are four levels of measurements, • Nominal measurement • Ordinal measurement • Interval measurement • Ratio measurement
- 12. Nominal measurement • It is the lowest of the four levels of measurements • It involves the assignment of number to represent categories or classes of things. • They have no quantitative values Gender Habitat male urban female rural slum
- 13. Ordinal measurement • Ordinal measurement ranks object based on their relative standing on a specific attribute. • Order of ranking is imposed on categories. • It reflect only magnitude, and does not have equal intervals or an absolute zero point. Health status Income status poor low income fair middle income good upper income excellent
- 14. Interval measurement • In this level, there is specification of ranking of objects on an attributes of the distance between those objects. • There is more or less equal numerical distance between intervals. Eg: Body Temperature 10-20 degree 30-40 degree 50-60 degree
- 15. Ratio measurement • It is the highest level of measurement. • It represent continuous values • Has an absolute zero point Biophysical parameters -weight -height -blood pressure
- 16. TYPES OF STATISTICS Two types are there, • descriptive statistics • inferential statistics
- 17. DESCRIPTIVE STATISTICS • It deals with the enumeration, organization and graphical representation of data. Eg: census of india in this all residents are requested to provide information such as age, gender, religion, marital status, education, occupation etc. the data will be arranged into tables and graphs and describes the characters of the population.
- 18. INFERENTIAL STATISTICS • Inferential statistics provides the procedures to draw an inference about the conditions that exist in a large set of observations.
- 19. DESCRIPTIVE STATISTICS • Descriptive statistics are used to organize and summarize data to draw meaningful interpretations. • Descriptive statistics also allow the researcher to interpret the data meaningfully, so that research questions can be answered completely and appropriately.
- 20. Descriptive statistics is classified into, • Frequency distribution and graphical presentation • Measures of central tendency • Measures of dispersion • Measures of relationship ( correlation coefficient)
- 21. Frequency distribution • An appropriate presentation of data involves organization of data in such a manner that meaningful conclusions and inferences can drawn to answer the research question. • Quantitative data are generally arranged under frequency distribution and presented through tables, charts, graphs and diagrams.
- 22. TABLES • Tabulation means a systematic presentation of information contained in the data in rows and columns in accordance with some features and characteristics. • A table presents data in a concise, systematic manner. • Tabulation is the first step before data is used for analysis.
- 23. PRINCIPLES OF TABULATION • A table should be precise, understandable, and self explanatory. • Every table should have title, which is placed at the top of the table. The title must describe the content clearly and precisely. • Items should be arranged alphabetically or according to size or importance. • Rows and columns to be compared with one another should be brought together.
- 24. • The content of the table should be defined clearly and fully. • The unit of measurement must be cleared state. • Totals can be placed in the bottom of the columns. • Reference symbols can be directly placed beneath the table for any explanatory footnotes. • Two or three small table should be preferred to one large one.
- 25. PARTS OF TABLE • Table number: it should be placed on the top of the table. • Title: every table must have a suitable title. • Head notes: it is given just below the title in brackets for further description of the contents of the table. • Captions and stubs: captions are the headings designated for vertical columns and stubs are the headings for horizontal rows.
- 26. • Body of table: arrangement of data according to description given in the form of captions and stubs form the body of table. • Foot notes: when some contents of the table is not adequately explained, foot notes are used to explain those items. • Source notes: source note is used when secondary data is used to mention the source from which the data for the table or the table itself is retrieved.
- 27. TYPES OF TABLE • Frequency distribution table • Contingency table • Multiple response table • Miscellaneous table
- 28. Frequency distribution table • A frequency distribution is a table that displays the frequency of various outcomes in a sample. • Each entry in the table contains the frequency or count of the occurrences of values within a particular group or interval, and in this way, the table summarizes the distribution of values in the sample.
- 30. Contingency table • A table showing the distribution of one variable in rows and another in columns, used to study the correlation between the two variables.
- 32. Multiple response table When classification of the cases is done into categories that are neither exclusive nor exhaustive, we get what is called multiple responsible table.
- 34. Miscellaneous table • These tables are used to present data other than frequency or percentage distributions such as mean, median, mode, range, standard deviation etc. • A table is called miscellaneous when presentation of data cannot be classified under the frequency distribution table, contingency table or multiple response table.
- 35. Graphical presentation of data • Commonly we are using graphs and diagrams for presenting the data of research studies, which include bar diagram, pie diagram, histogram, frequency polygon, line graphs, cumulative frequency curves etc.
- 36. USES • They gives an overall view of entire data. • They are visually more attractive than other ways of presenting data. • It is easy to understand and memorize. • It facilitate comparison of data.
- 37. Construction of diagrams and graphs • They must have a title • The proportion between width and height be balanced. • The selection of scale must be appropriate. • Footnotes may be included wherever it is needed.
- 38. Types of diagram and graphs • The types include – bar diagram – pie diagram – Histogram – frequency polygon – line graphs – cumulative frequency curves
- 39. BAR DIAGRAM • It is a convenient, graphical device that is particularly useful for displaying nominal or ordinal data. • It is an easy method adopted for visual comparison of the magnitude of different frequencies. • Length of the bars drawn vertically or horizontally indicates the frequency of character
- 40. • If the bars are placed vertically it is called as vertical bar charts. • When the bars are placed horizontally, then it is known as horizontal bar charts
- 42. Points to remember… • The width of the bars should be uniform throughout the diagram. • The gap between the bars should be uniform through out • Bars may be vertical or horizontal
- 43. Types of bar diagram • SIMPLE BAR DIAGRAM • MULTIPLE BAR DIAGRAM • PROPORTION BAR DIAGRAM
- 47. PIE DIAGRAM • It is another useful pictorial device for presenting the data. • The total area of the circle represents the entire data under consideration. • The total angle of pie diagram should be 360 degree.
- 48. PIE DIAGRAM/ SECTOR DIAGRAM
- 49. HISTOGRAM • It is the most commonly used graphical representation of grouped frequency distribution. • Variable characters of different groups are indicated on horizontal line (x-axis) and the frequencies (number of observation) are indicated on the vertical line (y-axis).