STATISTICS PRACTICE TESTS
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quizes_qnt.docx1
In statistics, a population consists of:
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all people living in a country
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all people living in the area under study
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all subjects or objects whose characteristics are being studied
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a selection of a limited number of elements
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An independent group wants to determine if the consumption of gasoline has increased due to changes in price. The group randomly selects 320 gas stations from 12 different states and collects data from the month of the year when gas is the cheapest and from the month of the year when gas is the most expensive. The data shows no significant difference in gas consumption between the two months. In this example, what is the variable being studied?
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The price of gasoline.
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The 320 gas stations chosen.
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The 12 different states.
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The consumption of gasoline.
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Cross-section data are collected:
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for a qualitative variable
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on different elements for the same variable for different periods of time
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on different elements at the same point in time
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on the same variable for the same variable at different points in time
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The Ohio lottery involves selecting 5 numbers from 5 different bins. This is an example of sampling
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with replacement.
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without replacement.
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A simple random sample is a sample drawn in such a way that:
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each member of the population has a 0.10 chance for being included in the sample
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every tenth element of an arranged population is included
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each sample of the same size has an equal chance of being selected
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each member of the population has some chance of being included in the sample
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Under inferential statistics, we study
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how to make decisions about a mean, median, or mode
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how a sample is taken from a population
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the methods to make decisions about one or more populations based on sample results
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tables composed of summary measures
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A continuous random variable is a random variable that can:
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assume only a countable set of values
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assume any value in one or more intervals
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assume no continuous random frequency
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have no random sample
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The population distribution is the probability distribution of the:
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population means
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population data
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population probabilities
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whole population of a country
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The population distribution is the probability distribution of the:
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population means
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population data
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population probabilities
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whole population of a country
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The sampling error is:
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an error that occurs when a sample of 30 or more members is drawn
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the difference between the value of a sample statistic and the value of the corresponding population parameter
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an error that occurs when a sample of fewer than 30 members is drawn
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an error that occurs during collection, recording, and tabulation of data
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To use an F distribution, the random variable must be:
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a continuous random variable
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a discrete random variable
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a qualitative random variable
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either a discrete or a continuous random variable
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Which of the following is not a characteristic of the normal distribution?
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The total area under the curve is 1.0
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The value of the mean is always greater than the value of the standard deviation
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The curve is symmetric about the mean
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The two tails of the curve extend indefinitely
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The units of an F distribution:
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can be negative, zero, or positive
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are always positive
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are always negative
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are always nonnegative
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For a two-tailed test, the p-value is:
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the area under the curve between the mean and the observed value of the sample statistic
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twice the area in the tail under the curve on the side which the sample statistic lies
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twice the area under the curve between the mean and the observed value of the sample statistic
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the area in the tail under the curve on the side which the sample statistic lies
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The null hypothesis is a claim about a:
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parameter, where the claim is assumed to be true until it is declared false
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statistic, where the claim is assumed to be true until it is declared false
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parameter, where the claim is assumed to be false until it is declared true
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statistic, where the claim is assumed to be false until it is declared true
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The confidence level of an interval estimate is denoted by:
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(1-β)*100%
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(1-α)*100%
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α
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β
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Two samples drawn from two populations are independent if:
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two samples selected from the same population have no relation
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the selection of one sample from one population does not affect the selection of the second sample from the second population
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the selection of one sample from a population is related to the selection of the second sample from the same population
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the selection of one sample from a population is not related to the selection of the second sample from the same population
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The values assigned to a population parameter based on the value(s) of a sample statistic are:
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the probability distribution
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the probabilities
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a sampling distribution
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estimate(s)
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A sample of 126 corporate managers and another sample of 168 college professors produced mean job-related stress scores of 7.35 for the managers and 6.86 for the professors. Suppose that the standard deviations of the stress scores are 1.12 for the managers and 1.82 for the professors. The null hypothesis is that the mean stress scores are the same for corporate managers and college professors, while the alternative hypothesis is that the mean stress score for managers is different from the mean stress score for professors. The significance level for the test is 1%. What are the critical values of z?
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-3.09 and 3.09
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-1.96 and 1.96
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-2.58 and 2.58
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-2.33 and 2.33
