Principles of Sampling and Data Presentation Flashcards
Is the set of complete collection or totality of all
possible values of the variable
Population (N)
A subset or sub-collection of elements drawn from a
population.
Sample (n)
Define the Target Population
Select a Sampling frame
Determine if probability or non-probability sampling method will be chosen.
Plan procedure for selecting sampling units
Determine sample size
Select actual sampling units
Conduct fieldwork
Stages in the Selection of a Sample
In this technique elements of the sample are selected through lottery.
Simple random sampling
o This technique of sampling is done by taking every element in the population
assignment of number as a part of the sample.
o To select the systematic sample of n elements from a population of N element, we
divide the N element in the population in the n groups of kth element.
Systematic sampling
Population under this technique is being divided into sections (or cluster), randomly
select some of these cluster as the member of the sample size.
Cluster sampling
o In this technique, the population is subdivided into at least two different sub-population
(or strata) that share the same characteristics and then the elements of the sample
are drawn from its stratum proportionately.
o We used this formula to compute for proportional stratified sampling technique
Stratified sampling
In this technique, the elements of the sample are being selected according to the
criteria or rules set
Purposive sampling
In this technique, the sample are being selected from a particular place at specified
time preferred
Convenience sampling
In this technique, the researcher asks respondents to give referrals to other possible
respondents
Snowballing sampling
In this technique, the sample size is limited on the required number or subject in the
study
Quota sampling
METHODS OF PRESENTING DATA
Textual
Tabular
Graphical
used to provide contextual
information and are fundamentally presented in paragraphs or sentences.
Textual presentation
one of the simplest means to summarize a set of observations and can be used for all
types of numerical data. It is useful in summarizing and comparing quantitative information coming
from different variables and different units and consequently be presented together.
TABLE PRESENTATION
The proportion of the total number of observations that appears in that interval.
It is computed by dividing the number of values within an interval by the total number of values
in the table, multiplied by 100% to obtain the percentage of values in the interval
useful for comparing sets of data that contain unequal numbers of observation.
Relative Frequency
percentage of the total number of observations that have a value less than or equal to
the upper limit of the interval
It is calculated by summing the relative frequencies for the specified interval and all previous
ones
Cumulative Relative Frequency
simplify complex information by using images and emphasizing data patterns or trends, and
are useful for summarizing, explaining, or exploring quantitative data.
GRAPH PRESENTATION
Popular type of graph used to display a frequency
distribution for nominal or ordinal data.
BAR CHARTS
depicts a frequency distribution for discrete or continuous data.
It is a bar graph in which the horizontal scale represents classes and the vertical scale
represents frequencies.
The horizontal axis displays the true limits of the various intervals.
The true limits of an interval are the points that separate it from the intervals on either side
HISTOGRAMS
Useful for comparing individual categories with the total.
PIE CHART
constructed by placing a point at the
center of each interval such that the height of
the point is equal to the frequency or relative
frequency associated with that interval.
Points are also placed on the horizontal axis
at the midpoints of the intervals immediately
preceding and immediately following the
intervals that contain observations.
The points are then connected by straight
lines
FREQUENCY POLYGONS
Another type of graph that can be used to summarize a set of discrete or continuous
observations.
Uses a single horizontal axis to display the relative position of each data point in the group
One-Way Scatter Plots
similar to one-way scatter plots in that they require a single axis; instead of
plotting every observation, however, they display only a summary of the data
Box Plots
depict the relationship between two different continuous measurements.
Each point on the graph represents a pair of values;
The scale for one quantity is marked on the horizontal axis, or x-axis, and the scale for the
other on the vertical axis, or y-axis
Two-Way Scatter Plots
Similar to a two-way scatter plot in that it can be
used to illustrate the relationship between
continuous quantities.
Each point on the graph represents a pair of values.
Adjacent points are connected by straight lines
Useful for representing time-series data
Useful for studying patterns and trends across data
Also appropriate for representing not only timeseries data, but also data measured over the
progression of a continuous variable such as
distanc
Line Graphs
sampling technique in which every member of a population has a known
and equal chance of being selected
Probability sampling-
sampling technique where the odds of any member being selected
for a sample cannot be calculated
Non-probability sampling
