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27 Cards in this Set
- Front
- Back
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What is a discrete variable? |
yes/no decision |
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What is a continuous variable? |
monetary amounts |
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What kind of a population parameter is a point estimate? |
a population parameter that is a single numerical value (e.g. mean, variance, standard distribution) |
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What is the term for an estimate of a population parameter that is a range of numerical numbers? |
interval estimate (e.g. confidence interval) |
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What are the main measures of central tendency? |
- mean - median - mode |
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Whar does a right (positively) skewed frequency distribution implicate? |
- mean is larger than median - many medium- and low-value items and a few high-value items |
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What is typical example for a right skewed frequency distribution? |
accounts receivable |
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What does a left (negatively) skewed frequency distribution implicate? |
- mean is smaller than median - a few low-value items and many medium- and high-value items |
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What is the best estimate for central tendancy of asymmetrical distributions? |
median is not biased by extremes |
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What does dispersion express with regard to a population or a sample? |
variability within the elements of a population or a sample |
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By what is a population's variability measured? |
standard deviation |
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What area does 1 standard deviations cover under a normal distribution curve? |
68% |
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What area do 2 standard deviations cover under a normal distribution curve? |
95,5% |
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What area do 3 standard deviations cover under a normal distribution curve? |
99,7% |
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What can be estimated using a pilot sample? |
standard deviation of a population |
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What is the standard error of the mean? |
the standard deviation of the distribution of sample means |
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What is the standard error used for? |
computation of precision (confidence interval) |
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How is the standard error of the mean calculated? |
population's standard deviation / (number of sample items)^1/2 |
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The larger the standard error, the... |
wider the confidence interval (the larger the precision) |
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What does the coefficient of variability measure? |
the relative variability within the data |
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How is the coefficient of variability measured for a sample? |
standard deviation of the sample/the mean |
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What is the other expression for the t-distribution? |
- Student's distribution |
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To what kind of statistics can the t-distribution only be applied? |
parametric statistics, i.e. some numeric value that is calculated for all items in the population
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What is the t-distribution used for? |
- for estimating a parametric statistic's (e.g. mean) standard deviation of a very small sample using a t-table |
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In what kind of testing is the chi-square distribution used for? |
for testing hypotheses concerning populations, i.e. whether the sample is likely to be from the population |
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How are hypotheses concerning populations tested using the chi-square distribution? |
based on a comparison of the sample variance and the estimated population variance |
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How is a reasonableness test performed? |
by comparing an estimated amount with a recorded amount |
