# 1.2 Practice Questions

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question
Explain the difference between a stratified sample and a cluster sample
In a stratified sample, random samples from each strata are included. In a cluster sample, the clusters to be included are selected at random and then all members of each selected cluster are included.
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Explain the difference between a simple random sample and a systematic sample.
In a simple random sample, every sample of size n has an equal chance of being included. In a systematic sample, the only samples possible are those including every kth item from the random starting position
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Consider the students in your statistics class as the population and suppose they are seated in four rows of 10 students each. To select a sample, toss a coin. If it comes up heads, you use the 20 students sitting in the first two rows as your sample. If it comes up tails, you use the 20 students sitting in the last two rows as your sample. 1)Does every student have an equal chance of being selected for the sample? Explain. A)Yes, your seating location ensures an equal chance of being selected. B)Yes, your seating location and the randomized coin flip ensure equal chances of being selected. C)No, the coin flip does not ensure an equal chance of being selected. D)No, your seating location does not ensure an equal chance of being selected. 2)Is it possible to include students sitting in row 3 with students sitting in row 2 in your sample? A)Sometimes it is possible with this described method of selections. B)Yes, it is possible with this described method of selection. C)No, it is not possible with this described method of selection. 3)Is your sample a simple random sample? Explain. A)No, this is not a simple random sample. It is a cluster sample. B)No, this is not a simple random sample. It is a stratified sample. C)Yes, this is a simple random sample. D)No, this is not a simple random sample. It is a systematic sample. 4)Describe a process you could use to get a simple random sample of size 20 from a class of size 40. A)Assign each student to a pair 1, 2, . . . , 20 and use a computer or a random-number table to select 10 pairs. B)Assign each student a number 1, 2, . . . , 40 and use a computer or a random-number table to select 20 students. C)Assign each student a group 1, 2, 3, 4 and use a computer or a random-number table to select 2 groups. D)Assign each student a number 1, 2, . . . , 20 and use a computer or a random-number table to select 10 students.