The following
are examples of errors in the analysis of the sample problem. In each case,
explain what is wrong.
1. A student was given this question: Researchers indicate
that about 20% of college students abstain from drinking alcohol each year. Suppose
you took a random sample of 85 college students from across the nation and
calculated 
(the proportion who say they abstain from
alcohol). Describe the sampling distribution of .
The student
gave the following answer:
SD( ) = 
= .0434
Is this
answer complete? Explain.
2. Suppose that a student claims to have gotten a sample
proportion of .38 orange candies in a sample of 25 candies. Explain how you
know that he is mistaken.
3. A student is told that 73% of all flowers bought for
Valentine’s Day are bought by men and is asked to identify the parameter.
Explain what is wrong with each of the following answers:
a. All Valentine’s Day flowers bought by men
b. All flowers bought on Valentine’s Day
c. Whether or not the flowers were bought by a man
d. The proportion who buy flowers on Valentine’s Day
4. Suppose that 70% of all Americans take a shower more
often than they take a bath. Then suppose we simulate 1000 samples with 80 people
in each sample, recording the sample proportion who take a shower more often
than a bath for each sample. Finally, suppose that a student is asked to
determine the standard deviation of the 1000 simulated sample proportions, and
he calculates
.
Identify the
error in this calculation.