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Stat 271
Major 1
Student Name
ID#
).
1. Which of the following statements is correct regarding the Central
Limit Theorem (CLT) ?
is always equal to the population
(a) CLT states that the sample mean
mean µ
(b) CLT states that the sampling distribution of
can be approximated by a
normal distribution if n ≥ 30
(c) CLT is applied regardless of the sample size n
(d) CLT states that the sampling distribution of µ is approximately normal,
provided n ≥ 30
2. If all possible samples of size n are drawn from a large population
with a mean of 20 and a standard deviation of 5, then the standard
error of the sample mean equals 1.0 only for samples of size
3. Number of different samples of size n = 3 that one can obtain by
sampling using SRSWR (simple random sampling with replacement)
from a population of N = 5 distinct elements is
4. Suppose that a random sample of 60 observations is selected from a
population with mean 80 and variance 36. What is the probability that
the sample mean exceeds 82.8 ?
5. Which of the following is correct ?
(a) A point estimate is an estimate of the range of a population parameter
(b) An interval estimate is an estimate of the range of a sample statistic
(c) A point estimate is a single value estimate of a population parameter
(d) An interval estimate is an estimate of the value of a population parameter
6. Estimation is best defined as
(a) a process of inferring the values of unknown population parameters from
those of known sample statistics
(b) a process of inferring the values of unknown sample statistics from those
of known population parameters
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(c) any procedure that views the parameter being estimated not as a constant,
but as a random variable
(d) a sampling procedure that gives the same value for the population
parameter regardless of the sample realization
7. In order to estimate the average number of miles that students who
live off-campus commute to classes every day, the following statistics
were given : n = 60, = 6.21 and s = 2. The point estimate of the true
population mean µ is
8. The margin of error is
(a) the difference between the point estimate and the true value of the
population parameter
(b) a critical value
the estimator
(c) the smallest possible sampling error
(d) None of the above
times the standard error of
9. In developing an interval estimate for a population mean, a sample of
40 observations was used. The interval estimate was 17:25 ±2:42. Had
the sample size been 160 instead of 40, the interval estimate would have
been
(d) 34.50 ± 4.82
10. A 99% confidence interval estimate for a population mean µ is
determined to be 85.58 to 96.62. If the confidence level is reduced to
90%, the confidence interval for µ
(a) becomes wider
(b) remains the same
(c) becomes narrower
(d) None of the above
11. Which of the following is not a part of the formula for constructing a
confidence interval estimate of the population proportion ?
(a) A point estimate of the population proportion
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(b) The standard error of the sampling distribution of the population
proportion
(c) The confidence coefficient
(d) The value of the population proportion
12. The lower limit of a confidence interval at the 95% level of
confidence for the population proportion if a sample of size 100 had 30
successes is
13. When estimating a population mean µ, where the population
standard deviation σ is known, we can, with confidence level 1 - α,
(a)
define the limits of an interval estimate of
(b) define the limits of an interval estimate of
(c) choose a smaller z value and construct a narrower confidence interval
(d) choose a larger z value and construct a wider confidence interval
14.
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