Questions Exam prep
Following a dramatic drop of 500 points in the Dow Jones Industrial Average in September 1998, a poll
conducted for the Associated Press found that 92% of those polled said that a year from now their
family financial situation will be as good as it is today or better. Which of the following terms describes
the number 92%?
(a) statistic.
(b) sample.
(c) sample parameter.
(d) population parameter.
(e) population. - correct answers(a) statistic.
What is distribution of values taken by a statistic in all possible samples of the same size from the same
population called?
(a) the probability that the statistic is obtained.
(b) the population parameter.
(c) the variance of the values.
(d) the sampling distribution of the statistic.
(e) the distribution of sample data. - correct answers(d) the sampling distribution of the statistic.
If a statistic used to estimate a parameter is such that the mean of its sampling distribution is equal to
the true value of the parameter being estimated, what is the statistic said to be?
(a) random
(b) biased
(c) a proportion
(d) unbiased
(e) non-varying - correct answers(d) unbiased
Suppose you take a random sample of size 25 from a population with mean of 120 and a standard
deviation of 15. Your sample has a mean of 115 and a standard deviation of 13.8. Which of the following
has a mean of 120 and a standard deviation of 3?
(a) the distribution of the population
(b) the distribution of the sample data.
(c) the sampling distribution of the sample mean.
(d) the sampling distribution of the population mean. (e) No important distribution related to this
situation has the given mean and standard deviation. - correct answers(c) the sampling distribution of
the sample mean.
In order to use the formula to calculate the standard deviation of the sampling distribution of the
sample mean, which of the following conditions must be met?
*I. n>30
II. The population's distribution is approximately Normal.
III. The sample size is less than 10% of the population size.*