[MMW] Part 2: Introduction to Statistics

Nominal Level of Measurement

It applies to data that consists of names, labels, or categories.

Nominal Level of Measurement

There are no implied criteria by which the data can be ordered from smallest to highest.

Examples: gender, sports, blood type, civil status, brand of vaccine injected, etc.

Ordinal Level of Measurement

It applies to data that can be arranged in order or rank.

Ordinal Level of Measurement

The differences between the data values either cannot be determined or are meaningless.

Examples: ranking of students, military ranks, sizes of shirt, etc.

Interval Level of Measurement

It applies to data that can be arranged in order; Differences between data values are meaningful.

Interval Level of Measurement

Data at this level have no true, or meaningful zero.

Examples: Temperature in degree Celsius, test results, grades, IQ, etc.

Ratio Level of Measurement

It applies to data that can be arranged in order. Both differences between data values, and ratio of data values are meaningful.

Ratio Level of Measurement

Data at the ratio level have a true or meaningful zero.

Example: area of a circle, distance travelled, volume of water, etc.

1. Nominal Level of Measurement

2. Ordinal Level of Measurement

3. Interval Level of Measurement

4. Ratio Level of Measurement

Level or Scales of Measurements (4)

Collection of Data

This is the first step in conducting a study or research after the formulation of the research problem. Compilation of primary and secondary sources of information

Collection of Data

The integration of different sources will consolidate the writeup of the report.

Primary Data

are first-hand information that is gathered directly from the source, such through personal interviews.

Secondary Data

are data that have been collected for another purpose. These are data derived from books, encyclopedias, journals, magazines, and other research or studies conducted by other individuals.

Primary Data

Secondary Data

Classifications of Data (2)

Interview Method

Referred to as direct method. It involves an interviewer and an interviewee.

Advantage/s: The researcher can get more accurate answers or responses since clarifications can be made during the interview.

Disadvantage/s: It can be time-consuming and costly.

Questionnaire Method

Referred to as indirect method. The questionnaire (also called survey) is a set of questions given to a sample of people.

Advantage/s: It can save time and money and it can cover a lot of respondents.

Disadvantage/s: Questions can’t be clarified; return rate of questionnaire can be low

Observation Method

Making use of the different human senses in gathering information.

Advantage/s: Data collected by observation, are, thus, more objective and generally more accurate.

Disadvantage/s: Limiting factor to observe; time-consuming and costly

Registration or Census

Governed by enacted laws. Covers a large scope of population or the entire population.

Some government agencies are Land Transportation Office (LTO), Commission on Elections (COMELEC) and Philippine Statistics Authority (PSA)

Experimental Method

Involves performing an experiment and then collecting the data to be further analyzed.

laboratory and field.

(Under Experimental Method) two types of experiments

Experimental Method

It is used when establishing cause-and-effect relationships.

Interview Method

Questionnaire Method

Observation Method

Registration or Census

Experimental Method

Methods of Collecting Data (5)

Summary Statistics

It is a part of descriptive statistics that summarizes and provides the gist of information about the sample data.

Mean

arithmetic average; it is the most common and most useful average

Median

middlemost value

Mode

most frequently occurring value

Mean

Median

Mode

Measures of Central Tendency (3)

Range

distance from the lowest to the highest value (using two data points)

Variance

uses all data points; it is the average distance that each score is from the mean.

Standard deviation

is obtained by the square root of variance. Is represented by 𝜎 (population standard deviation or s (sample standard deviation)

Pie Chart

is a circular chart divided into sectors, illustrating relative magnitudes usually in percentages. In a ___, the area is proportional to the quantity it represents.

Line Graph

(also known as a line plot or line chart) is a graph which uses lines to connect individual data points that display quantitative values over a specified time interval.

Line Graph

uses data point markers that are connected by straight lines to aid in visualization.

Bar Graph

is a graph with rectangular bars. The graph usually compares different categories. Although the graphs can be plotted vertically or horizontally, the most usual type of bar graph is vertical.

Grouped Bar Graph

it is a way to show information about sub-groups of the main categories.

Stacked Bar Chart

it also shows sub-groups, but the sub-groups are stacked on the same bar.

Segmented Bar Graph

each bar shows 100% of the discrete value.

Histogram

is a display of statistical information that uses rectangles to show the frequency of data items in successive numerical intervals of equal size.

independent variable

In the most common form of histogram, the ______ is plotted along the horizontal axis and the dependent variable is along the vertical axis.

Scatterplots

is a graphic tool used to display the relationship between two quantitative variables.

Tables

It is used when: Trend is not important, Number of values are small, To complement other data presentation format

Two-way Tables

Relationships between two categorical variables can be shown through a two-way table. It is also known as a contingency table, cross-tabulation table, or a cross-classifying table.