Practical Statistics S302 2021 PDF

Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Practical Statistics S302 Sanaa Ahmed Enan, M.Sc. Department of Statistics Faculty...

Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Practical Statistics S302 Sanaa Ahmed Enan, M.Sc. Department of Statistics Faculty of mathematical sciences and Informatics University of Khartoum 2021 Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples INTRODUCTION Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Outline 1 Introduction 2 Statistics Life Cycle 3 Terminologies 4 Data Collection 5 Questionnaire Design 6 Types of Variables 7 Examples Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Introduction The world is becoming quantitative. data are becoming enormous, and data scientist profession is becoming the most wanted profession in almost every sector that includes decision making. The Idea behind that is when you are in a situation of decision making you ask these questions: 1 Where you can find appropriate data to describe the situation 2 What are the right techniques used to change these data into information 3 How you can validate these information Voila! Moment Here make sound decision based on the most appropriate scientific technique. Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Statistic life cycle 1 Question need an answer, a problem need a solution or more generally Decision to be made (setting objectives). 2 Population(s) and sample(s). 3 Data collection and validation. 4 Descriptive and/or Comparative analysis. 5 presenting and interpreting results. 6 have we met our goals? 7 if not, redo. Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Definitions Population Vs. Sample The population is set of all units of interest to a researcher. Typically, the population is not observed, but we wish to make statements or inferences concerning it. Whilst the samples are observed subsets of the units. Samples are used to describe and make inferences concerning the populations from which they arise and they are selected for study in some prescribed manner. Parameter Vs. Statistic Parameter is a characteristic concerning the population upon which we make our inference/estimation. Statistic is the same characteristic but coming the sample. Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Data Collection From where we collect data? Two resources: Primary Resource here we collect data directly from the study unit. Secondary Resource data are being collected indirectly. How we can collect data? Various data collection instruments are used: 1 Observation 2 Focus Group 3 Interviews 4 Surveys/Questionnaires 5 Check lists Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Characteristics of a well designed questionnaire A well-designed questionnaire should meet the research objectives. It should obtain the most complete and accurate information possible. It should make it easy for respondents to give the necessary information and for the interviewer to record the answer, and it should be arranged so that sound analysis and interpretation are possible. It would keep the interview brief and to the point and be so arranged that the respondent(s) remain interested throughout the interview. Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Development of a questionnaire 1 Decide the information required. 2 Define the target respondents. 3 Choose the method(s) of reaching your target respondents. 4 Develop the question wording. 5 Decide on question content. 6 Put questions into a meaningful order and format. 7 Check the length of the questionnaire. 8 Make it fancy. 9 Train field personnel. 10 Pre-test the questionnaire. 11 Prepare and conduct the field work. 12 Develop the final survey form. Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Question contents Always link your question to research aims and objectives Keep your questions SHORT AND SIMPLE so the respondents have the best chance to understand them. The question should only ask one question. The question must be worded appropriately for the target population. The question must be clear, precise, and unambiguous. Make the question simple to understand. Avoid unnecessary adjectives and adverbs. Avoid negatives and double negatives. Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Question contents Avoid Emotional Responses Dont use emotionally loaded words. Use wording that minimizes the risk of socially acceptable responses The question wording should not lead the respondent to answer in a particular way. Put the Question in Context The wording of the question should not make unwarranted assumptions. The wording should follow a natural order from the previous question. Closed Question Must Include The Appropriate Answer Set Translate the Questionnaire (if necessary) Consider The Response When Developing the Question Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Random Variables and their classifications What is the variable It’s a quantity that vary from object to object or from subject to subject. What is the random variable It’s a variable that takes on defined set of values with different probabilities. A way to classify a random variables is: Dependent Vs.Independent Another way is to classify them into: Quantitative Vs. Qualitative Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Dependent Vs. Independent variables Applications of statistics are often based on comparing outcomes among groups of subjects. That is, we would like to compare outcomes among different populations. The variable(s) we measure as the outcome of interest is the dependent variable, or response. The variable that determines the population a measurement arises from is the independent variable (or predictor). Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples Qualitative Vs. Quantitative variables Qualitative variables are categorical variables that can be broken into two types: ( Nominal or Ordinal), and Quantitative variables are numerical variables that can be broken onto two types:(Discrete or Continuous) Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples EXAMPLES Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples EXAMPLES Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples EXAMPLES Sanaa Ahmed Enan, M.Sc. S302  Introduction Statistics Life Cycle Terminologies Data Collection Questionnaire Design Types of Variables Examples EXAMPLES Sanaa Ahmed Enan, M.Sc. S302