Chapter 8/21 | | | | | | | | | | |
What is sampling error? | | | | | | | | | | |
A sampling error is the difference between the sample statistic and it's corresponding population parameter. |
Could the value of the sampling error be zero? | | | | | | | | |
Yes | | | | | | | | | | | | |
If it were zero, what would this mean? | | | | | | | | | |
This would mean that the sample is a represwtative of the the population, and the result is true of the population | | | | | | | | |
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Chapter 8/22 | | | | | | | | | | |
List the reasons for sampling. Give an example of each reason for sampling. | | | | | |
Time - getting answers from the entire population would be time consuming | | | | | |
Example - a company wanting to survey every household in the United States could send out a survey team but they can only complete so many surveys in a reasonable amount of time |
Cost - it would be very costly to survey the entire population, samples allow data to be collected at a more reasonable cost | |
Example - if a company mailed flyers to collect data from households, mailing to a sample could cost $40,000, mailing to an entire population could cost over $1 million |
Ability - it is impossible to get data from all of some populations, as some populations are infinite | | | |
Example - If a researcher collected data from bees, then he will use a sample of the bee population because it is impossible to get data from every bee. |
Destructive nature - some test consumes or damages materials used in the testing, and there may not be enough of that material to test the entire population |
Example - a manufacturer will stress test the steel wire they make but they will only test a sample of the wire, because if they tested it all they would have no wire left to sell. |
Adequate results - samples provide results that are...