Which of the following statements about sampling errors is FALSE（）
A. Sampling errors are errors due to the wrong sample being selected from the population.
B. Sampling error is the difference between a sample statistic and its corresponding population parameter.
C. Sampling errors will vary from one sample to the next.
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A stock priced at $100 has a 70 percent probability of moving up and a 30 percent probability of moving down. If it moves up, it increases by a factor of 1.02. If it moves down, it decreases by a factor of 1/1.02. What is the probability that the stock will be $100 after two successive periods（）
A. 9%.
B. 42%.
C. 21%.
The standard normal distribution is most completely described as a:（）
A. symmetrical distribution with a mean equal to its median.
B. normal distribution with a mean of zero and a standard deviation of one.
C. distribution that exhibits zero skewness and no excess kurtosis.
When is the t- distribution the appropriate distribution to use The t -distribution is the appropriate distribution to use when constructing confidence intervals based on:（）
A. small samples from populations with known variance that are at least approximately normal.
B. large samples from populations with known variance that are nonnormal.
C. small samples from populations with unknown variance that are at least approximately normal.
Which one of the following statements about the t - distribution is TRUE（）
A. The t- distribution is the appropriate distribution to use when constructing confidence intervals based on large samples.
B. Compared to the normal distribution, the t -distribution is more peaked with more area under the tails.
C. The t - distribution approaches the standard normal distribution as the number of degrees of freedom becomes large.
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