5.1 Data Management

• Statistics is a branch of mathematics that deals with the collection, organization, analysis, interpretation, and presentation of data.
• Descriptive statistics involves processes concerning the description and summary of important features of a collected data.
• Inferential statistics tend to make generalizations and draw conclusions about a population based on the data collected from the representative of the population.
• Population – refers to total amount of things.
• Sample – refers to a small part of the population that is used for the study.
• Sample size – the total amount of things in a sample
• Variable is any characteristic, number, or quantity that can be measured or counted and can take on different values.
• Variables are used to represent data collected from observations, surveys, or experiments, and they can vary among individuals.
• Qualitative (Categorical) Variables: These represent characteristics or attributes that can be categorized but not measured numerically.
• Quantitative Variables: These represent numerical measurements or counts, such as height, weight, and scores.
• Data collection is the process of gathering and measuring information on variables of interest in an organized systematic way
• Interview - It can encounter be done between the through a interviewer face-to-face and the interviewee where the interviewer records the responses by writing down or with the use of video/voice recorder.
• Questionnaires - It provide a list of questions which can be answered through email or handing over personally to the source. This consumes lesser time than the interview method.
• Experiments - It involve deliberately manipulating or changing one or more variables to observe the effects on another variable, known as the dependent variable. Through controlled conditions and systematic observation, ... establish cause-and-effect relationships between variables.
• Direct observation - It is done by directly observing the behavior and other activities of samples under study. It is usually conducted when samples are not able to respond or data to be collected are to be observed.
• utilizing existing records - Are known to be the most convenient way of collecting data. It is conducted by gathering information from agencies which have already collected the data for certain purposes.
• The textual method - This method is used to elaborate important figures in a paragraph of text.
• The graphical method - This method uses graphs like line, column, bar, and pie charts to visually represent data, making it easier to interpret. Visualizations help reveal patterns, trends, and relationships that may not be obvious in raw data. Notably, graph titles should be placed at the bottom.
• A line graph is useful for presenting historical data and effectively shows the movement or trend of a series over time.
• Column graph is the most appropriate way to compare amounts in a time series, where the focus is on differences in magnitude rather than trends. This type of graph is also useful for displaying the frequency distribution of a quantitative variable and the bars are displayed vertically.
• A bar graph compares frequencies of categorical data using rectangular bars, where the bar lengths are proportional to the values they represent, all bars have equal width and the bars of the graph are displayed horizontally.
• A pie graph is circular and divided into sectors, with each sector's arc length proportionate to the value it represents. Instead of displaying frequency, each sector represents the percentage of data categories, totaling 100%.
• The tabular method uses rows and columns to present a dataset, similar to a frequency distribution table, and may include frequencies, percentages, averages, standard deviations, and totals. Tables can also be used to compare relationships between variables.
• 1. Table Heading – contains the table title and number
  2. Caption – contains the heading of the columns
  3. Stubs – contains the heading of the rows
  4. Body – contains figures from the data