MADAM SITI AISYAH BINTI ZAKARIA INSTITUT MATEMATIK KEJURUTERAAN UNIVERSITI MALAYSIA PERLIS

Students, like professional people, must be able to read and understand the various statistical studies performed in their fields. To have this understanding, they must be knowledgeable about the vocabulary, symbols, concepts, and statistical procedures used in these studies. Students and professional people may be called on to conduct research in their fields, since statistical procedures are the basic to research. To accomplish this, they must be able to design experiments; collect, organize, analyze, and summarize data; and possibly make reliable predictions or forecasts for future use. They must also be able to communicate the results of the study in their own words. Students and professional people can also use the knowledge gained from studying statistics to become better consumers and citizens. For ex. They can make intelligent decisions about what products to purchase based on consumer studies about government spending based on utilization studies and so on. 2 MADAM SITI AISYAH BINTI ZAKARIA

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Examples statements present some statistics in business: Bill Gates is the richest American with a net worth $43 billion (Forbes, September,30,2002). A total of 35billion transactions were handled by the Visa system during 2001 (Forbes, September 16,2002). On average, a household carried a credit card balance in $8562 in 2001 (Newsweek, April 1, 2002). On average, a wedding in America costs $20,357 (Smart Money, June 2002). Based on the 2000 census, 40.5 million households have two vehicles. (Source: Census Bureau) 4 MADAM SITI AISYAH BINTI ZAKARIA

DATA  Data is the facts and figures collected, analyzed, and summarized for presentation and interpretation  A data with lot of observations usually looks non informative that is we cannot get much information with the raw data.  Raw data is also called as ungrouped data.  Data refers to quantitative or qualitative attributes of a variable or set of variables. - Example :- the whole numbers that represents the scores of students.  Data is categorized by two :- - quantitative data - qualitative data  Data should be summarized in more informative way such as graphical, diagrams and charts. 5 MADAM SITI AISYAH BINTI ZAKARIA

 Element – entities on which data are collected ( ex. In note)  Variable – is a characteristic of interest for the elements  Observation – the set of measurements obtained for a particular element MADAM SITI AISYAH BINTI ZAKARIA 6

 Measurement Levels and the Appropriate Averages ALL DATA Qualitative data Quantitative data Nominal Car makes, Days of Week, Gender Ordinal TV channel Ranks and title Calendar dates Interval and Ratio Sales ($) Accounts Receivable Market share ModeMedian Mean 7 MADAM SITI AISYAH BINTI ZAKARIA

 There are four measurement scales :- i. Nominal ii. Ordinal iii. Interval iv. Ratio 1) Nominal  only for qualitative classification.  the weakest data measurement where numbers are used to represent an item / characteristic.  each data should not be treated as numerical since relative size has no meaning.  no order or ranking can be imposed on the data. (e.g : gender – male =1, female = 2) 8 MADAM SITI AISYAH BINTI ZAKARIA

2) Ordinal  it is possible to rank order all the categories according to some criterion.  classifies data into categories that can be ranked ( no precise difference ) (e.g : grades – A,B,C,D and collegiate class – freshman, sophomore, junior, senior) 3) Interval  have the property that the distances between categories are defined by fixed and equal units.  is ranks of data  quantity and compare the size of difference between two observations (precise difference do exist) (example :For age, a change from age 21 to 22 is the same for changes age 31 to 42) 9 MADAM SITI AISYAH BINTI ZAKARIA

4) Ratio  The highest level of measurement and allows for all basic arithmetic operations including division and multiplication.  Has the property that a zero point is naturally defined.  The mode, mean, median can be used to describe interval and ratio data.  Poses all the characteristics of interval measurement.  True zero exist. (E.g : Production of 20 units per hour (ratio level) is twice the production of 10 units per hour) 10 MADAM SITI AISYAH BINTI ZAKARIA

Variable QuantitativeQualitative Discrete (e.g, number of houses, cars accidents Continuous (e.g., length, age, height, weight, time) e.g., gender, marital status 11 MADAM SITI AISYAH BINTI ZAKARIA

1) Quantitative variable  A variable that can be measured numerically.  Data collected on a quantitative variable are called quantitative data.  There are two types of quantitative variables:- i. Discrete Variable A variable whose values are countable, can assume only certain values with no intermediate values. ii. Continuous Variable A variable that can assume any numerical value over a certain interval or intervals. 2) Qualitative variable  A variable that cannot assume a numerical value but can be classified into two or more nonnumeric categories.  Data collected on such a variable are called qualitative data. 12 MADAM SITI AISYAH BINTI ZAKARIA

1) Cross Section Data  Data collected on different elements at the same point in time or for same period of time.  An example of cross-section data which is giving of six companies for the same period (2007) :- Company2007 Charitable Giving (millions of dollars) Home Depot42 Macy`s35.2 Wal-Mart337.9 Best Buy31.8 Target168.9 Lowe`s27.5 Table 1.2 : Charitable Givings of Six Retailers in MADAM SITI AISYAH BINTI ZAKARIA

2) Time-Series Data  Data collected on the same element for the same variable at different points in time or for different periods of time.  Example, a Movieplex with 8 screens would count as 8 toward the total number of screens. YearTotal Indoor Movie Screens , , , , , ,198 Table 1.3 : Number of Movie Screens 14 MADAM SITI AISYAH BINTI ZAKARIA

DATA SOURCES SOURCES OF DATA Primary Data (data collected by the researcher) Examples:- i.Personal Interview ii.Telephone Interview iii.Questionnaire iv.Observations Secondary Data (already collected/ published by someone else) Examples: - From books, magazines, annual report, internet 15 MADAM SITI AISYAH BINTI ZAKARIA

STATISTICS  Numerical facts  Field or discipline of study  Collection of methods for planning experiments, obtaining data and organizing, analyzing, interpreting and drawing the conclusions or making a decision.  Example : (In NOTE) 16 MADAM SITI AISYAH BINTI ZAKARIA

STATISTICS DESCRIPTIVE STATISTICS INFERENTIAL STATISTICS Using tables, graphs & summary measures Using sample result in making decision or predict about a population. Also called inductive reasoning or inductive statistics. 17 MADAM SITI AISYAH BINTI ZAKARIA

Descriptive Statistics  a study on data summary or describes a collection, data organization (presentation of data in a more informative way such as graphical, diagrams and charts).  In general divided by two categories :- - Data presentation (display) - Tabular - Charts/graphs - Statistics 18 MADAM SITI AISYAH BINTI ZAKARIA

Inferential Statistics  Consists of generalizing from samples to population, performing estimations and hypothesis tests, determining relationships among variables, and making predictions.  Area statistics which are deal with decision making procedures.  Population – consists of all subjects (human or otherwise) that are being studied.  Sample – is a group of subjects selected from a population.  Example :- - In order to find the salary of a college graduate, we may select 2000 recent college graduates, find the starting salaries and make decision based on the information. 19 MADAM SITI AISYAH BINTI ZAKARIA

STATISTICAL ANALYSIS USING EXCEL Example 1.1 :- Following table shows data for income tax returns for 1995 to 2001 that were filed electronically. Get the sum of income tax for all years and get average of the income tax for those 7 years. i. Data is key in using Excel. Figure 1 20 MADAM SITI AISYAH BINTI ZAKARIA

ii. To get sum of income tax for all years, type =SUM(. iii. Select the range of cells (C4:C10) of numerical data, and close the bracket. Figure 2 21 MADAM SITI AISYAH BINTI ZAKARIA

iv. Press Enter, the sum should appear. Figure 3 22 MADAM SITI AISYAH BINTI ZAKARIA

v. To get, the average, the sum should divide by the number of years. vi. Type =AVERAGE(. vii. Select the range of cells for all years (C4:C10) and close bracket. viii.Press Enter. The average of income tax for those years should appear. Figure 4 23 MADAM SITI AISYAH BINTI ZAKARIA

 Population - Entire collection of individuals which are characteristic being studied.  Sample -Subset of population. Population Sample 24 MADAM SITI AISYAH BINTI ZAKARIA

 Census - Survey includes every member of population.  Sample survey - Collecting information from a portion of population (techniques)  Element -Specific subject or object about which information collected.  Variable - Characteristics which make different values. 25 MADAM SITI AISYAH BINTI ZAKARIA

 Observation -Value of variable for an element.  Data Set -A collection of observation on one or more variables. NameScore Mohd Amirul bin Hamdi90 Hashimah78 Element Variable Observation/ Measurement Table 1: Student’s Score for Business Statistic 26 MADAM SITI AISYAH BINTI ZAKARIA

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