Geologists have an interest in the structure and the history of the earth. A geologist can go back in time by drilling deep into the ground, retrieving a core sample, estimating the ages of the various layers, and examining the composition.
A timeline can be built of the entire area from where the core sample was drilled. A geologist may retrieve several core samples to confirm the history of the earth's structure in that sampled area. Mountains, lakes, and unstable ground can easily impede a simple random sampling of a desired geographical area, therefore what is the most realistic sampling method that represents the actual drillings, comparisons, and scientific examinations of several core samples within the same geographical area?
A) Systematic sampling B) Cluster sampling
C) Multistage sampling D) Stratified sampling
Q. 2The produce manager at a farmer's market was interested in determining how many oranges a person buys when they buy oranges.
He asked the cashiers over a weekend to count how many oranges a person bought when they bought oranges and record this number for analysis at a later time. The data is given below in the table. The random variable x represents the number of oranges purchased and P(x) represents the probability that a customer will buy x apples. Determine the mean number of oranges purchased by a customer.
x 1 2 3 4 5 6 7 8 9 10
P(x) 0.05 0.19 0.20 0.25 0.12 0.10 0 0.08 0 0.01
A) 5.50 B) 3 C) 4 D) 3.97
Q. 3The human resources department of a large, well-known telecommunications firm is behind schedule in sampling the job satisfaction of the company's employees.
In an effort to catch-up, the HR manager quickly goes down an alphabetical list of employees and e-mails a survey to every tenth employee. An neutral third party collects all surveys and ensures all of the selected employees respond to the survey. What sampling method best describes what the HR manager is doing?
A) Multistage sampling B) Cluster sampling
C) Stratified sampling D) Systematic sampling
Q. 4A mega-discount chain store just opened a new clothing store in town emphasizing mainly women's clothing. Before opening, management had to decide whether to only carry either men's, women's, boys', girls', or infants' clothing.
After performing representative sampling of potential customers from each of these groups, it was decided to carry only women's clothing. Identify the type of sampling used in this example.
A) Stratified sampling B) Multistage sampling
C) Systematic sampling D) Cluster sampling
Q. 5A baseball player is asked to swing at pitches in sets of four. The player swings at 100 sets of 4 pitches. The probability distribution for making a particular number of hits is given below.
Determine the mean for this discrete probability distribution.
x 0 1 2 3 4
P(x) 0.02 0.07 0.22 0.27 0.42
A) 3.5 B) 3 C) 2 D) 4
Q. 6A newly-premiered play just ended that evening at a local theater. Theater management briefly interviews every ninth person leaving the theater to see if that person will recommend the play at that theater to other people.
Identify the type of sampling used in this example.
A) Multistage sampling B) Systematic sampling
C) Stratified sampling D) Cluster sampling
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