# Shared Flashcard Set

## Details

Stats Econ Sp 2012
MIdterm 2 Multiple choice questions
26
Economics
Not Applicable
04/05/2012

Term
 1.A numerical description of the outcome of an experiment is called aa.descriptive statisticb.probability functionc.varianced.random variable
Definition
 D
Term
 2. A probability distribution showing the probability of x successes in n trials, where the probability of success does not change from trial to trial, is termed aa.uniform probability distributionb.binomial probability distributionc.Hyper-geometric probability distributiond.normal probability distribution
Definition
 b
Term
 3. A continuous random variable may assumea.any value in an interval or collection of intervalsb.only integer values in an interval or collection of intervalsc.only fractional values in an interval or collection of intervalsd.only the positive integer values in an interval
Definition
 a
Term
 4. An experiment consists of making 80 telephone calls in order to sell a particular insurance policy. The random variable in this experiment is aa.discrete random variableb.continuous random variablec.complex random variabled.simplex random variable
Definition
 b
Term
 5. Which of the following statements about a discrete random variable and its probability distribution are true?a.Values of the random variable can never be negative.b.Some negative values of f(x) are allowed as long as f(x) = 1.c.Values of f(x) must be greater than or equal to zero.d.The values of f(x) increase to a maximum point and then decrease.
Definition
 c
Term
 6. The expected value of a random variable isa.the value of the random variable that should be observed on the next repeat of the experimentb.the value of the random variable that occurs most frequentlyc.the square root of the varianced.None of these alternatives is correct.
Definition
 a
Term
 7. The expected value for a binomial probability distribution isa.E(x) = Pn(1 - n)b.E(x) = P(1 - P)c.E(x) = nPd.E(x) = nP(1 - P)
Definition
 c
Term
 8. The center of a normal curve isa.always equal to zerob.is the mean of the distributionc.cannot be negatived.is the standard deviation
Definition
 b
Term
 9. For a continuous random variable x, the probability density function f(x) representsa.the probability at a given value of xb.the area under the curve at xc.the area under the curve to the right of xd.the height of the function at x
Definition
 d
Term
 10.For any continuous random variable, the probability that the random variable takes on exactly a specific value isa.1.00b.0.50c.any value between 0 to 1d.almost zero
Definition
 d
Term
 12. A continuous random variable is uniformly distributed between a and b. The probability density function between a and b isa.zerob.(a - b)c.(b - a)d.1/(b - a)
Definition
 d
Term
 18. If we consider the simple random sampling process as an experiment, the sample mean isa.always zerob.always smaller than the population meanc.a random variabled.exactly equal to the population mean
Definition
 c
Term
 19. Whenever the population has a normal probability distribution, the sampling distribution of is a normal probability distribution fora.only large sample sizesb.only small sample sizesc.any sample sized.only samples of size thirty or greate
Definition
 c
Term
 22. For a population with any distribution, the form of the sampling distribution of the sample mean isa.sometimes normal for all sample sizesb.sometimes normal for large sample sizesc.always normal for all sample sizesd.always normal for large sample sizes
Definition
 d
Term
 23. The absolute value of the difference between the point estimate and the population parameter it estimates isa.the standard errorb.the sampling errorc.precisiond.the error of confidence
Definition
 a
Term
 26. A sample of 200 elements from a population with a known standard deviation is selected. For an interval estimation of , the proper distribution to use is thea.normal distributionb.t distribution with 200 degrees of freedomc.t distribution with 201 degrees of freedomd.t distribution with 202 degrees of freedom
Definition
 a
Term
 15. Parameters area.numerical characteristics of a sampleb.numerical characteristics of a populationc.the averages taken from a sampled.numerical characteristics of either a sample or a population
Definition
 b
Term
 16. Sampling distribution of is thea.probability distribution of the sample meanb.probability distribution of the sample proportionc.mean of the sampled.mean of the population
Definition
 a
Term
 17. Since the sample size is always smaller than the size of the population, the sample meana.must always be smaller than the population meanb.must be larger than the population meanc.must be equal to the population meand.can be smaller, larger, or equal to the population mean
Definition
 d
Term
 16. Sampling distribution of is thea.probability distribution of the sample meanb.probability distribution of the sample proportionc.mean of the sampled.mean of the population
Definition
 a
Term
 17. Since the sample size is always smaller than the size of the population, the sample meana.must always be smaller than the population meanb.must be larger than the population meanc.must be equal to the population meand.can be smaller, larger, or equal to the population mean
Definition
 d
Term
 24. When s is used to estimate , the margin of error is computed by usinga.normal distributionb.t distributionc.the mean of the sampled.the mean of the population
Definition
 b
Term
 27.A 95% confidence interval for a population mean is determined to be 100 to 120. If the confidence coefficient is reduced to 0.90, the interval for a.becomes narrowerb.becomes widerc.does not changed.becomes 0.1
Definition
 a
Term
 28. When the level of confidence decreases, the margin of errora.stays the sameb.becomes smallerc.becomes largerd.becomes smaller or larger, depending on the sample size
Definition
 b
Term
 29. The sample size needed to provide a margin of error of 2 or less with a .95 probability when the population standard deviation equals 11 isa.10b.11c.116d.117
Definition
 d
Term
 30. When constructing a confidence interval for the population mean and the standard deviation of the sample is used, the degrees of freedom for the t distribution equalsa.n-1b.nc.29d.30
Definition
 a
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