A student would like to estimate the mean length of words in a book report he just finished writing. He selects a random sample of 20 words and determines the mean length to be 4 characters. Later, he discovers how to use a built-in function of his word-processing program that reveals that the mean length of all words in his book report is 4.3 characters. Which of the following statements is true?
Answer
A
The population is all words in the book report and the sample is the random sample of 20 words.
B
The population is the random sample of 20 words and the sample is all words in the book report.
C
The population is the mean length of all words in the book report and the sample is the mean length of the 20 randomly selected words.
D
The population is the mean length of the 20 randomly selected words and the sample is the mean length of all words in the book report.
Explanation
The population is the entire group the student wants to learn about: all the words in his book report. The sample is the smaller group he actually selected and measured: the random sample of 20 words. The means of 4 and 4.3 characters are statistics and a population value, respectively; they are not the population and sample themselves.
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