3. process of gathering and measuring
information on variables of interest, in an
established systematic fashion that enables
one to answer stated research questions,
test hypotheses, and evaluate outcomes
27. can be answered y checking slots or stating
simple names or brands
arrangement of questions should e
carefully planned
limit questions to essential information
28. Two Major Ways of
Selecting Sample Units from
a Population
29. known as simple random
sampling
picking things at random means
picking things without bias or any
predetermined choice
A. Probability Sampling
32. the selection of each member of
the population is left adequately
to chance, and every member of
the population has an equal
chance of being chosen
2. Table of Random Numbers
33. used when there are only few
sample units to be selected
a. Direct Selection Method
34. Two Ways of Conducting the
Remainder Method:
b. Remainder Method
35. 1. When the number taken from
the table of random numbers is
subtracted from the upper limit
within which this number falls, the
remainder is the sample unit.
b. Remainder Method
36. 2. When the upper limit of the set is
subtracted from the number taken
from the random tables and yields a
number equal or less than N, the
remainder is the sample unit.
b. Remainder Method
37. used when the population is too
large to handle
B. Restricted Random Sampling
39. units are obtained by drawing
every nth element of the
population
1. Systematic Sampling
40. nth = Total no. of elements in the population
Desired Sample Size
nth = N
n
41. ex: population 50,000; sample size 100; margin of
error 10%. Determine the nth term
nth = N
n
= 50,000/100
= 500
42. a. Stratified Sampling
the population is divided into groups based on
homogeneity
the distribution of units is proportional to the
total number of units in each stratum
Types of Systematic Sampling
43. 1) Identify N and its different strata
2) Divide the members of the population into
percent shares
3) multiply each percent share by n sample units
to get the actual number of sample units for
each stratum
steps:
44. Example
population is 50,000
sample units is 100
margin of error is 10 %
25,000 belong to high income group
10,000 belong to middle income group
15,000 belong to low income group
strata
46. STRATA NUMBER OF
POPULATION
PERCENT SHARE
(N/n)
High-income
group
25,000/50,000
Middle-income
group
10,000/50,000
Low-income
group
15,000/50,000
TOTAL 50,000
0.5 or 50%
0.2 or 20%
0.3 or 30%
100%
47. STRATA Sample size times the
percent share
Number of Sample Units
High-income
group
100 x 0.5
Middle-income
group
100 x 0.2
Low-income
group
100 x 0.3
TOTAL
50
20
30
100
48. b. Cluster Sampling
an area sample: geographical basis
districts or blocks
heterogeneous groups
Types of Systematic Sampling
49. c. Multi-Stage Sampling
uses several stages in getting the samples
from the general population
useful in conducting a nationwide survey
Types of Systematic Sampling
50. not all members of the population are given
equal chances: sample
non-probability sampling
chooses its sample
used in market research or employment
department
2. Non-Random Sampling
51. a. Purposive Sampling
choosing samples based on a criteria and rules
by the researcher
Types of Non-Random Sampling
52. b. Quota Sampling
the researcher limits the number of his
samples based on the required number of
subject under investigation
Types of Non-Random Sampling
53. c. Convenience Sampling
the researcher conducts a study at his
convenient time, preferred place or venue
Types of Non-Random Sampling