5 Statistics is also defined as, it is a science of collecting data, processing, organizing and interpreting also taking more effective decisions on the basis of sample information. There are two categories of statistics: Descriptive Statistics Inferential Statistics Descriptive statistics is that in which we describe the characteristics of population like mean, median, standard deviation etc. Inferential statistics is that in which we draw influence on the basis of sample information about the population that is called inferential statistics (inference; statistical results).
6 Population: Total area under discussion is called population. The number of observations in a finite population is called size of the population and is denoted by N. Sample: An enough and representative part of population is called sample. The number of observations in a sample is called size of the sample and is denoted by n. INTRODUCTION TO STATISTICS
7 Functions of Statistics: Statistics has the following major functions(uses). Statistics helps in collecting and presenting data in a systematic and meaningful form i.e., summarizes the larger set of data into an easily understand form. e.g., there is a lot of students in a particular college does not give an exact information as the statement that 480 students studying in the college i.e., numerical facts give more precise information than facts expressed in general terms. Statistics facilitates comparisons of data e.g, the price indices of a given year easily compare with the price indices of previous years.
8 INTRODUCTION TO STATISTICS Statistics assists in highlighting the important features of data and studied relationships among different facts Statistics helps in prediction or forecasting. Statistics help in formulations of suitable policies also sound and effective planning in any field of inquiry. Statistics helps in formulating and testing of hypothesis through observed data.
9 INTRODUCTION TO STATISTICS Importance of Statistics in different fields: State Management. ( Budget, Unemployment, Census etc) Pure Science. Mathematical Science. Psychology, Education and Sociology. Business.
10 INTRODUCTION TO STATISTICS Banks. Insurance Companies. Economic & Economic Development Companies. Agriculture. Research.
11 INTRODUCTION TO STATISTICS There are two types of population: Finite population Infinite population Population which consists of countable or fixed number of values is called finite population. Examples? whereas population which consists of infinite number of values is called infinite population. Examples?
12 Parameter: All numerical values calculated from population is called parameter. And all these values are denoted by Greek letters. e.g mean and standard deviation are denoted by μ and σ respectively Statistic: All numerical values calculated from sample is called statistic. And all these values are denoted by small letters. e.g mean and standard deviation are denoted by ӯ and s respectively. If we study the total population of fish in pond which is 100 then it is called as parameter but if we study specific (20 fish) then it is called as statistic. INTRODUCTION TO STATISTICS
13 INTRODUCTION TO STATISTICS Variable The characteristics which varies from individual to individual is called variable e.g. height variable, blood pressure level etc. Types of variable Quantitative Qualitative A variable which can be measureable numerically is called quantitative whereas a variable which cannot be measured numerically only can be described is called qualitative e.g. marital status of man.
14 INTRODUCTION TO STATISTICS Constant The characteristic which does not change is called constant. Examples? Data The information collect from the respondent is called data. Types of data: Primary data Secondary data Primary data A collection of data at initial stage without using statistical tool is called as primary data. Examples?
15 INTRODUCTION TO STATISTICS Sources of Primary Data Personal Investigation Through Investigators Through Local Sources Through Telephone Through Internet Through Questionnaire Secondary data It is an organized or compact form of data. It is obtained from any organizations, institutions, governments and semi- governments etc. The primary data converted into secondary data after applying some statistical tools. Examples?
16 INTRODUCTION TO STATISTICS Sources of Secondary Data Government Organizations Semi-government Organizations Teaching and Research Organizations Research Journals and Newspapers
17 INTRODUCTION TO STATISTICS Scales of Measurement Measurement: Measurement refer to Assigning of number to observations or objects. Scaling: Scaling is a process of measuring. Four Scales of Measurements Nominal Scale Ordinal Scale Interval Scale Ratio Scale
18 INTRODUCTION TO STATISTICS Nominal Scale (Weakest form of measurement) The classification or grouping of the observations into mutually exclusive qualitative categories or classes is said to constitute a nominal scale. e.g. Sex, Race, Religion, Country Rainfall may be classified as Heavy, Moderate, Light Ordinal Scale (When numbers are allocated in some order) It includes the characteristics of nominal scale and in addition has a property of ordering or ranking of measurements. Attitude scale Strongly agree, agree, disagree Social scale Upper, middle, lower Performance of players Excellent, good, fair, poor
19 INTRODUCTION TO STATISTICS Interval Scale It has separate categories, like nominal scales and also has ordered categories like ordinal scales. But the interval measurements has no true zero point. Temperature (80oF and 40oF is 26.7oC and4.4oC) Ratio Scale In this scale the intervals are consistent along the entire scale. The ratio measurements has true zero point. Height of plant, weight of students, volume, length,
20 INTRODUCTION TO STATISTICS Questions: Explain that the given statement follows which types of data. Sex of insect. Weights of plants. Major crops of Pakistan. Level of satisfaction. Teaching standards. Temperature measured in Fahrenheit.