STATS CH 9
A new sampling distribution of the mean is created by switching to a a) new sample size. b) new population. c) new sample size and a new population. d) new sample size or a new population.
D
A random sample of 100 college students is taken from the student body of a large university Assume that, in fact, a population mean of 20 hours and a population standard deviation of 15 hours describe the weekly study estimates for the entire student body. About 68 percent of the sample means in this sampling distribution should be between a) 18.50 and 21.50 hours. b) 16.50 and 20.50 hours. c) 19 and 21 hours. d) 17 and 23 hours.
A
A random sample of 100 college students is taken from the student body of a large university. Each student estimates the number of hours spent studying each week. Therefore, the sampling distribution of the mean is a) approximately normal in shape. b) very compact. c) equal to the population. d) centered about the sample mean.
A
Any generalization from a sample to a population should be viewed as a) tentative. b) necessary. c) erroneous. d) desirable.
A
Construction of a sampling distribution from scratch is feasible when the population is a) very small. b) real. c) large. d) composed of observations that are whole numbers.
A
It wouldn't make sense to talk about a sampling distribution for a) individual observations. b) proportions. c) medians. d) standard deviations.
A
The standard error of the mean serves as a rough indicator of the average amount by which sample means deviate from a) the population mean. b) each other. c) some population characteristic. d) the one observed sample mean.
A
A random sample of 100 college students is taken from the student body of a large university Assume that, in fact, a population mean of 20 hours and a standard deviation of 15 hours describe the weekly study estimates for the entire student body. Therefore, the sampling distribution of the mean has a mean that a) approximates 20 hours. b) equals 20 hours. c) lies within a couple of hours of 20. d) equals the one observed sample mean.
B
A random sample of 100 college students is taken from the student body of a large university Assume that, in fact, a population standard deviation of 15 hours describes the weekly study estimates for the entire student body. Therefore, the sampling distribution of the mean has a standard error that is a) very compact. b) equal to 1.50 hours. c) less than 15 hours. d) known.
B
An important implication of the formula for the standard error is that whenever the sample size equals two or more, the variability of the sampling distribution is______________ the variability of the population. a) equal to b) less than c) more than d) approximately the same as
B
Increasing the size of the sample a) guarantees that the sample will be representative of the population. b) reduces the variability of the sampling distribution. c) changes the variability of the population. d) produces all of the above effects.
B
The central limit theorem concentrates on changes in the ________________ of a sampling distribution. a) size b) shape c) central tendency d) variability
B
When sample size is large, it's most likely that the mean for any single sample has a value that is a) equal to the population mean. b) intermediate. c) highly variable. d) larger than that for the population mean.
B
When sample size is sufficiently large, about ______ percent of all sample means are within one standard error of the sampling distribution mean. a) 50 b) 68 c) 95 d) 100
B
A particular observed sample mean a) equals the population mean. b) equals the mean of the sampling distribution. c) most likely has a value in the vicinity of the population mean. d) is equally likely to have a value either near to, or far from, the population mean.
C
A random sample of 100 college students is taken from the student body of a large university Assume that, in fact, a population mean of 20 hours and a population standard deviation of 15 hours describe the weekly study estimates for the entire student body. About 95 percent of the sample means in this sampling distribution should be between approximately a) 18 and 20 hours. b) 18 and 22 hours c) 17 and 23 hours. d) 15 and 25 hours.
C
A sampling distribution a) reflects the shape of the underlying population. b) is constructed from scratch. c) serves as a bridge between sample and population. d) remains unchanged even with shifts to new populations.
C
Given that the population standard deviation equals 40 and that the sample consists of 25 observations, the standard error of the mean equals a) 0.80 b) 5 c) 8 d) 40
C
Greek letters are used to describe characteristics of a) samples and populations. b) samples and sampling distributions. c) sampling distributions and populations. d) samples, sampling distributions, and populations.
C
The sampling distribution of the mean describes a) the entire population. b) the entire sample. c) all sample means that could occur just by chance. d) the sampled distribution.
C
As used in the definition of a sampling distribution, all possible samples refers to a) the number of samples required to survey an entire population. b) an infinitely large number of samples. c) a very large number of samples. d) the number of different ways that a sample can be selected from a population.
D
In serious applications, sampling distributions are a) constructed from scratch. b) restricted to relatively few possibilities. c) employed only at the outset of the analysis. d) deduced from the theory of statistics.
D
The central limit theorem specifies a change in the shape of a) any distribution. b) the population. c) the sample d) the sampling distribution.
D
The mean of the sampling distribution equals the population mean because a) each sample is a replica of the population. b) a sampling distribution is the same as a complete survey of the population. c) a population is the sampling distribution. d) chance differences among sample means are neutralized.
D
To obtain an exact replica of a population, take a a) random sample. b) large sample. c) representative sample. d) complete survey of the population.
D