8.DATA DESCRIPTIVE

8.DATA DESCRIPTIVE 8.1 INTRODUCTION OF DATA 8.2 FREQUENCY DISTRIBUTIONS 8.DATA DESCRIPTIVE 8.3 MEASURES OF LOCATION 8.4 MEASURES OF DISPERSION

SUBTOPIC 8.1 : Introduction of Data LECTURE 1 OF 6 8.DATA DESCRIPTIVE SUBTOPIC 8.1 : Introduction of Data

OBJECTIVES (a) Clarify the meaning and the use of statistics (b) Define the basic terms; population, parameter, sample, statistic and variables. (c) Define quantitative and qualitative (d) Define the discrete and continuous data (e) Clarify ungrouped and grouped data

SET INDUCTION These are Mathematics marks for 30 students who are taking mid-semester test 12 , 23, 24, 45, 34, 48, 56, 63, 23, 44, 69, 78, 84, 95, 98, 67, 73, 69, 58, 70, 40, 88, 59, 47, 37, 15, 17, 36, 63, 38 How to interpret these marks?

WHAT IS STATISTICS ? ~ Is the science that deals with collecting, classifying, presenting, describing, analyzing and interpreting data to enable us to draw conclusions and making reasonable decisions ~ Divided into 2 categories (a) Descriptive statistics (b) Inferential statistics

Descriptive statistics ~ The activities of collecting, classifying, presenting and describing quantitative data Inferential statistics ~ The part dealing with technique and method of interpretation of the results obtained from the descriptive statistics

WHAT IS POPULATION ? ~ Is the entire (complete) collection of data whose properties are analyzed. It contains all the subjects of interest. ~ Can be of any size, its items need not be uniform but must share at least one measurable feature.

WHAT IS SAMPLE? ~ A portion of population selected for study ~ Is any set of entities, cases, subjects, items or experimental units chosen from the population.

Eg: To study the heights of students in KMPP Population Sample KMPP's students H9 Eg: To study the heights of students in KMPP

WHAT IS RANDOM SAMPLE? ~ A random sample is a sample selected in such a way that each element of the population has the same chance of being selected

WHAT IS PARAMETER ? WHAT IS statistic? ~ Is a numerical measurement describing some characteristics of a population ~ Eg: The population mean , variance WHAT IS statistic? ~ Is a numerical measurement describing some characteristics of a sample ~ Eg: The sample mean ,variance

WHAT IS VARIABLES ? ~ Any measured characteristic or attribute that differs for different elements ~ For example, if the weight of 30 subjects were measured, then weight would be a variable. ~ Can be classified as quantitative or qualitative

WHAT IS quantitative VARIABLES ? ~ The variable being studied is numeric ~ measured on an ordinal, interval, or ratio scale ~ eg: If the time it took them to respond were measured, then the variable would be quantitative.

WHAT IS qualitative VARIABLES ? ~ The variable being studied is non-numeric ~ Called "categorical variables” ~ Measured on a nominal scale ~ eg: gender, educational level, eye colour If five-year old students were asked to name their favourite colour, then the variable would be qualitative.

WHAT IS DATA ? ~ A set of data is a collection of observation, measurements or information obtained ~ Can be classified as quantitative or qualitative ~ Can be presented in various way

WHAT IS quantitative DATA ? ~ Quantitative data refers to observations which can be measured numerically or counted ~ Can be divided into discrete data and continuous data ~ eg: length, time, temperature and mass

WHAT IS qualitative DATA ? ~ Qualitative data are not in numerical form but instead assigned as attributes ~ eg: race, marital status, age, sex

Discrete data ~ Is a data that can only take exact and countable values ~ For example: a) The number of students in a class. b) The number of cars sold on any day at a car dealership. c) Number of persons in a family. d) Number of students in a class.

Continuous data ~ Is a data can take any value over certain interval and can be measured to a certain degree of accuracy (correct to certain decimal places) ~ For example: a) The weight of students in a class. b) The time taken to complete an examination. c) The amount of soda in a 150ml can. d) Income of a family.

WHAT IS UNGROUPED DATA ? ~ (a) Raw data (b) Not in the term of interval (c) Frequency distribution that has been arranged in order ~ Example: (i) 3,5,6,2,5,2,4,6,5 (ii) Number of books 1 2 3 Frequency 7 4

WHAT IS GROUPED DATA ? ~ The data can be grouped into class interval before the frequency distribution is constructed ~ The table constructed is called frequency distribution table ~ Example: Height (cm) 150-155 155-160 160-165 165-170 Frequency 2 8 6 5

Examples: Determine whether the data obtained is discrete or continuous data. The number of books sold by stationary shop. The time taken to travel from Kuala Terengganu to Batu Pahat The numbers of A’s for UPS in this session The weight of the students in a practicum The diameter of twenty spheres Discrete Continuous Discrete Continuous Continuous

REMARKS… All data are to be considered as sample unless otherwise stated in the questions.