Multiple Choice Identify the
choice that best completes the statement or answers the question.


1.

A news organization computes a confidence interval
from a sample survey designed to estimate the proportion of U.S. adults who own smart phones.
The interval is 43% to 53%. The margin of error for this confidence interval is


2.

A news organization computes a confidence interval
from a sample survey designed to estimate the proportion of U.S. adults who own smart phones.
The interval is 43% to 53%. The sample proportion used to construct this interval is


3.

A 95% confidence interval for the mean m of a population is computed from a random sample and found to be 12 ±_{ }4. We may conclude that
a)  95% of the time, when we estimate m, we will get the interval 8 to 16  b)  we can be 95% confident that the mean m is
between 8 and 16.  c)  95% of all data in
this distribution for this variable is between 8 and 16.  d)  there is a 95% probability that m is between
8 and 16. 


4.

A statistics student performs a survey to determine
the percentage of seniors at her school who are planning to go to college after graduation. Out of
the 186 students she surveys, 136 say they plan to go to college. The sample proportion for this
survey is


5.

A statistics student performs a survey to determine
the percentage of seniors at her school who are planning to go to college after graduation. Out of
the 186 students she surveys, 136 say they plan to go to college. The margin of error for a 95%
confidence interval for the true proportion of seniors at her school who plan to go to college is
closest to


6.

The t* for a onesample mean confidence interval with n = 28 observations and
95% confidence is
a)  2.052  b)  2.056  c)  2.048  d)  2.050 


7.

If the sample size for a survey is decreased, which
of the following would happen?
a)  the margin of error would
increase  b)  the margin of error would stay the
same  c)  the margin of error would
decrease  d)  the margin of error would become
negative 


8.

I compute a 99% confidence interval for m. Suppose I then compute a 90% confidence interval from the same data.
Which of the following statements is true?
a)  The 90% confidence interval would be
wider.  b)  The intervals would have the same
width.  c)  It is not possible to know which interval would be wider.  d)  The 99% confidence interval would be
wider. 


9.

A 99% confidence interval for the mean height of of
5th grade girls is found to be (57.5,62.3). The sample mean used to create this interval
is


10.

A 99% confidence interval for the mean height of of
5th grade girls is found to be (57.5,62.3). The margin of error of this interval
is
