A confidence interval for a ________ based on a normal approximation is almost identical to a t confidence interval for a mean of a set of 1s and 0s.
a.proportion
b.standard error
c.median
d.sample size
Q. 2
What sample size should be used if we would like to estimate the mean age of the individuals who are attend a university with a 95 confidence interval that has a width of at most 5 years? Assume the population is normally distributed with a standard deviation of 4.2 years.
a.The sample size should be 10.
b.The sample size should be 19.
c.The sample size should be 11.
d.The sample size should be 8.
Q. 3 Which of the following is the correct formula for a
confidence interval for
when both
and
are estimated?
a.
with
df =
n - 1
b.
with
df =
n - 1
c.
with
df =
n - 1
d.
Q. 4 If it is found that 10 randomly selected pickup truck owners get 17 mpg on average, what is the value for
when computing a 95 confidence for the population mean?
a.1.83
b.2.26
c.3.25
d.2.23
Q. 5 If a random sample of size
n is taken from any distribution with a mean of
, then which of the following is an unbiased estimator of
?
a.the average of the two extreme observations
b.the median
c.
d.the sample mean
Q. 6 What is the level of confidence associated with an interval for estimating the parameter
that has the form
?
a.90
b.95
c.10
d.99
Q. 7
If (0.049, 0.387) is a 95 confidence interval for a population mean, which of the following would be a 90 confidence interval calculated from the same set of sample data that was used to create the 95 confidence interval above?
a.(0.088, 0.348)
b.(-0.062, 0.498)
c.(0.018, 0.418)
d.(-0.01, 0.446)
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