Data Analysis Total Session Time: 120 minutes – PST06210 Operational Research
NTA Level 6 • Semester 2 • PST06210 Data Analysis Total Session Time: 120 minutes Operational Research • Source Session/Topic 23 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 23: Data Analysis Total Session Time: 120 minutes Prerequisites None Learning Tasks By the end of this session students are expected to be able to: Describe data in terms of frequency distribution, percentages and proportion Use figures to present data. Explain the difference between mean, mode and median Calculate the frequencies, percentages, proportion, ratios, rates means, medians, modes for major variables. Identify variables that are necessary for analysis of the collected data 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 05 minutes Presentation Introduction, Learning Tasks Presentation Description of Data in Terms of Frequency 2 15 minutes Brainstorming Distribution, Percentages and Proportion 10 minutes 3 Presentation Using Figures to Present Data. 20minutes Presentation 4 Group Difference Between Mean, Mode and Median discussion 20 minutes Calculation of the Frequencies, Percentages, 5 Presentation Proportion, Ratios, Rates Means, Medians, Modes for Major Variables. 40 minutes 6 Presentation Identification of Variables that are Necessary for ___________________________________________________________________________ PST 06210 Operational Research NTA Level 6 Semester 2 Facilitator Guide 228 Analysis of the Collected Data 7 05 minutes Presentation Key Points 8 05 minutes Presentation Evaluation 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: Description of Data in Terms of Frequency Distribution, Percentages and Proportion (10 minutes) Activity: Brainstorming (5 minutes) Ask students to brainstorm on the following question What is frequency distribution, percentages and proportion? ALLOWS few students to respond WRITE their responses on the flipchart or board CLARIFY and SUMMARISE by using the content below • Data analysis involves the production and interpretation of frequencies, tables, graphs, etc., that describe the data. o Frequency counts From the data master sheets, simple tables can be made with frequency counts for each variable. A frequency count is an enumeration of how often a certain measurement or a certain answer to a specific question occurs. For example Smokers 51 Non-smokers 93 Total 144 If numbers are large enough it is better to calculate the frequency distribution in percentages (relative frequencies): ___________________________________________________________________________ PST 06210 Operational Research NTA Level 6 Semester 2 Facilitator Guide 229 • 51/144 x 100 = 35% are smokers and 93/144 x 100 = 65% non-smokers. • This makes it easier to compare groups than when only absolute numbers are given. In other words, percentages standardize the data. • It is usually necessary to summarize the data from numerical variables by dividing them into categories. This process may include the following steps: o Inspect all the figures: What is their range? (The range is the difference between the largest and the smallest measurement.) o Divide the range into three to five categories. You can either aim at having a reasonable number in each category (e.g. 0-2 km, 3-4 km, 5-9 km, 10+ km for home- clinic distance) or you can define the categories in such a way that they are each equal in size (e.g., 20-29 years, 30-39 years, 40-49 years, etc.) o Construct a table indicating how data are grouped and count the number of observations in each group. STEP 3: Using Figures to Present Data (10 minutes) • Figures o Figures make the descriptive data more readable when you have many tables o Numerical data Histograms Line graphs Scatter diagrams maps o Categorical data Bar charts Pie charts • Bar charts o Is simplest and most effective means of illustrating qualitative data o Bars can either be horizontal or vertical o Eg.57 Adolescents from Kaloleni streets in Arusha were asked the following question: How often have you used cannabis for the past one year? This was closed question with the following possible answers o Frequently (more than 5 times), Occasionally ( 3 to 5 times), rarely (1 to 2 times)and never Categories Number Percentage Frequently 7 12.2 Occasionally 9 15.8 ___________________________________________________________________________ PST 06210 Operational Research NTA Level 6 Semester 2 Facilitator Guide 230 Rarely 10 17.5 Never 31 54.4 Total 57 100 Pie charts o Provides quick view of data presented in different form. o Used in qualitative number with few categories to avoid congestion Histograms ___________________________________________________________________________ PST 06210 Operational Research NTA Level 6 Semester 2 Facilitator Guide 231 o Numerical data are often presented in histograms o Which are similar to bar charts important difference is that in histogram ‗the bars‘ are connected (as long as there is no gap between the data where as in bar charts are not connected as the different categories are distinct entitles) Line graphs o Particularly useful for numerical data if you want to show Trend over time o It is easy to show two or more distribution in one graph as long as difference between lines are easy to distinguish e.g. age distribution between males and females STEP 4: The Difference Between Mean, Mode and Median (30 minutes) Activity: Small Group Discussion (20 minutes) DIVIDE students into small manageable groups ASK students to discuss on the following question • What is the difference between mean, mode and median? ALLOW students to discuss for 10 minutes ALLOW few groups to present and the rest to add points not mentioned CLARIFY and SUMMARIZE by using the contents below • Mean o The mean of a data set is also known as the average value. It is calculated by dividing the sum of all values in a data set by the number of values. o So, in a data set of