Notesale: Turn your study into money

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In Statistics, there are many different sampling techniques
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Probability Sampling- is a sampling technique wherein each member or
element of the population has an equal chance of being selected as the
members of the sample
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Non-Probability Sampling- is a sampling technique wherein members of the
sample are drawn or chosen from the population based on the judgement of
the researchers
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But this is use because it is convenient, economical, inexpensive
and easy to conduct
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1
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This is the
simplest sampling technique
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From there, we will draw our sample by
randomly picking our desired number of respondents
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David wants to send five students to attend a 5-day seminar about
environmental awareness campaign in Bronx, New York USA
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He can use the random sampling technique in
selecting the five students to avoid biases
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Stratified Random Sampling- this technique is use when our population do
not belong to the same category, bracket, class, or group
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Example, Joshua and his group wants to determine the average income of families
living in Lourdes Sur East
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If we use simple random sampling there is
a possibility or a chance that none of the families from the low-income families
might be chosen or a higher number of high-income families might be chosen

thus, making our study bias and unreliable
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Suppose the total number of families in Lourdes Sur East is 5,000 but Joshua and
his group only need 200 families
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Strata

Number of
Families

High

1,000

Average

2,500

Low

1,500

Percentage

Third, we must multiply each percentage by the desired number of families in the
sample
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2 x 200= 40

Average

2,500


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3 x 300= 60

Total 5000

Percentage

100%

# of families
in the sample

200

From the table, we see that if Joshua and his friends are going to select 200
families from the population of 5,000, they must draw 40 families from the highincome, 100 from the average-income, and 60 from the low-income group
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3
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Here is the formula
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Aguilar won at a raffle promo sponsored by Naval Group of
Companies
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However, he has 56 close friends
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Since he only needs
4 more that can go with him and he has 56 close friends, we have to divide the
number of population members by the number of desired sample size
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Next is to write the numbers 1 to 14 in a piece of
paper and draw one by lottery
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Therefore, 12th, 24th, 36th, and 48th close
friend shall go with him in the trip
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Cluster Sampling- also called area sampling because this is usually used
when large areas are considered as the population
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Sample group are chosen by random sampling
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Nogoy wants to make a nationwide study on the relationship
between smoking and death rate
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If three of 13 clusters or regions
are the desired sample units, the names of 13 clusters will be written on small
pieces of paper, then three will be picked at random using the lottery method
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So those are the four common sampling techniques under probability sampling
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1
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Example, Professor Merrit, a famous historian, needs to make a historical study
about Angeles City
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2
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Almost similar with stratified
random sampling however it is not done randomly
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Serafica, a convenience store owner, wants to know what is the
most common hair shampoo used by her male and female customers
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3
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It is selecting the available
respondents in your available time
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Asia, a news anchor, wants to know the opinion of Filipino about
the “Corruption is bad because… and win an iPod” issue
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4
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Example, in a car accident scene, the policemen interviews some people who
were on the crime scene during the time it happen until he gets enough
information to support the evidence

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