Basic Statistical Concepts – PST06210 Operational Research
NTA Level 6 • Semester 2 • PST06210 Basic Statistical Concepts Operational Research • Source Session/Topic 1 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 1: Basic Statistical Concepts Total Session Time: 120 minutes Prerequisites • None Learning Tasks By the end of this session students are expected to be able to: • Define common terms used in biostatistics • Explain the importance of different measures in statistics • Explain the application of statistics in data analysis Resources Needed • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers • Computer and LCD Projector SESSION OVERVIEW Activity/ Step Time Content Method 1 5 minutes Presentation Introduction, Learning Tasks 30 minutes Presentation 2 Definitions of common terms in Biostatistics Brainstorm 45minutes Presentation Importance of Different Measures in 3 Buzzing Statistics 30minutes Presentation 4 Application of Statistics in Data Analysis Brainstorming 5 05minutes Presentation Key Points 6 05 minutes Presentation Evaluation ___________________________________________________________________________ PST 06210 Operational Research NTA Level 6 Semester 2 Facilitator Guide 1 SESSION CONTENTS STEP1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Definition of common terms in Biostatistics (30 minutes) Activity: Buzzing (5 minutes) ASK students to pair up and buzz on the following question for 2 minutes • What is biostatistics? ALLOW few pairs to respond and let other pairs to add on points not mentioned WRITE their response on the flip chart/board CLARIFY and SUMMARIZE by using the content below • Biostatistics can be defined as the application of statistics to biological problems. • Many biomedical scientists consider it to mean the application of statistics specifically to medical problems. • For this group of people, therefore, biostatistics and medical statistics are synonymous Other terms: • Statistics can be defined in two forms: o First ―statistics‖ as a ―noun‖ means a descriptive measure computed from data of a sample i.e. numerical statement – information that is available in numbers). Examples of this include: Hospital data on the number of admissions for some condition in a period How much drug (e.g. Amoxicillin capsules) is distributed to health units – hospitals, health centers and dispensaries This first part of the subject is usually referred to as descriptive statistics o Secondly ―statistics‖ as a ―discipline‖ is a field of study concerned with: Collecting, organizing and summarizing and analysis of data in a systematic way. Drawing of inferences about a population on the basis of only a part of the population targeted. This second part, which, provides objective means of drawing conclusions, constitutes inferential statistics ___________________________________________________________________________ PST 06210 Operational Research NTA Level 6 Semester 2 Facilitator Guide 2 • Population o A collection of entities. o A statistical population means the largest collection of entities in which we have an interest. o Example we may be interested in looking at how may health facilities are given Amoxil in district X? • Sample o Part of a population. o Example number of health centers given Amoxil capsules. • Central tendency o Measures of central tendency provide a summary measure that attempts to describe data with a single value that represents the middle or center of its distribution. o There are three main measures of central tendency: the mean, median and mode Mean, arithmetic mean (X or M): • The mean of a data set is also known as the average value • The sum of the scores in a distribution divided by the number of scores in the distribution. It is the most commonly used measure of central tendency. • It is often reported with its companion statistic, the standard deviation, which shows how far things vary from the average. Median (Mdn): • The midpoint or number in a distribution having 50% of the scores above it and 50% of the scores below it. • The median of a data set is the value that is at the middle of a data set arranged from smallest to largest • If there are an odd number of scores, the median is the middle score. Mode (Mo): • The number that occurs most frequently in a distribution of scores or numbers • The mode is the most common observation of a data set, or the value in the data set that occurs most frequently. Quartile • A measure of statistical dispersion which divides a frequency distribution into equal groups each containing the same fraction of the total population • The first quartile (designated Q1) is the lower and cuts off the lowest 25% of data (the 25th percentile) ___________________________________________________________________________ PST 06210 Operational Research NTA Level 6 Semester 2 Facilitator Guide 3 • The second quartile (Q2), or the median, cuts the data set in half (the 50th percentile) • The third quartile (Q3) cuts off highest 25% of data, or the lowest 75% (the 75th percentile) Variations • Range (Ra): The difference between the highest and lowest scores in a distribution; a measure of variability. • Standard deviation (SD): The most stable measure of variability, it takes into account each and every score in a normal distribution. This descriptive statistic assesses how far individual scores vary in standard unit lengths from its midpoint of 0. For all normal distributions, 95% of the area is within 1.96 standard deviations of the mean. • Variance (SD2): A measure of the dispersion of a set of data points around their mean value. It is a mathematical expectation of the average squared deviations from the mean. STEP 3: Importance of Measures in Statistics (45 minutes) Activity: Buzzing (5 minutes) ASK students to pair up and buzz on the following questions for 2 minutes • What are the importance of different measures in statistics ALLOW few pairs to respond and let other pairs