Statistics- Sampling Techniques Review Questions with Correct Answers Already Passed
Random samples - Answers are selected by using
chance methods or random numbers.
ex random samples - Answers Number each object in the population; Place the numbered card in a box
and mix
them; Select as many card as needed to form the
sample.
Systematic samples - Answers Numbering each object in the population; Selecting every Kth value.
ex Systematic samples - Answers suppose there are 2000 students in an elementary school and a sample
of 50 students is needed.
Solution: give a number to each student. then find k=2000/50=40 and every 40th student would be
selected. Choose randomly the 1st student from 1 through 40.
Stratified samples - Answers are selected by Divide the population into groups (X {
typically: race, age, gender, religion, education}) Obtain a random or systematic sample of each
X; Put together the samples obtained in the previous
step for your ________.
ex stratified samples - Answers There are 500 students in a private school in which 350 are male and 150
are female. We need 11 students from each. Solution males k=350/11=31.81 approximately 31 round
down. Then randomly choose 1 from 31. then count from that number 31 times till you get 11 students.
same goes for females.
Cluster samples - Answers are selected by Divide the population into sections "often
geographical"; Obtain a random or systematic sample of each; Put together the samples obtained in the
previous step for your ________.
ex cluster samples - Answers assume town A has 500 families. In this town there are 20% low income
families, 50% middle income families, and 30% upper-income families. We need 30 families from each
cluster.
Solution .20(500)=100 low income .5(500)=250 middle income .3(500)=150 upper income.
sample - Answers part of a population
Random samples - Answers are selected by using
chance methods or random numbers.
ex random samples - Answers Number each object in the population; Place the numbered card in a box
and mix
them; Select as many card as needed to form the
sample.
Systematic samples - Answers Numbering each object in the population; Selecting every Kth value.
ex Systematic samples - Answers suppose there are 2000 students in an elementary school and a sample
of 50 students is needed.
Solution: give a number to each student. then find k=2000/50=40 and every 40th student would be
selected. Choose randomly the 1st student from 1 through 40.
Stratified samples - Answers are selected by Divide the population into groups (X {
typically: race, age, gender, religion, education}) Obtain a random or systematic sample of each
X; Put together the samples obtained in the previous
step for your ________.
ex stratified samples - Answers There are 500 students in a private school in which 350 are male and 150
are female. We need 11 students from each. Solution males k=350/11=31.81 approximately 31 round
down. Then randomly choose 1 from 31. then count from that number 31 times till you get 11 students.
same goes for females.
Cluster samples - Answers are selected by Divide the population into sections "often
geographical"; Obtain a random or systematic sample of each; Put together the samples obtained in the
previous step for your ________.
ex cluster samples - Answers assume town A has 500 families. In this town there are 20% low income
families, 50% middle income families, and 30% upper-income families. We need 30 families from each
cluster.
Solution .20(500)=100 low income .5(500)=250 middle income .3(500)=150 upper income.
sample - Answers part of a population
