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Stat Tutor

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0:39

Correct. The average (mean) for all students at your school is a population mean. While this will change through time (prices go up and down – remember time series from Chapter 1), at any one point it is considered to be a fixed amount.

Incorrect. The average (mean) for all students at your school is a population mean. While this will change through time (prices go up and down – remember time series from Chapter 1), at any one point it is considered to be a fixed amount.

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1:52

Correct. Larger samples with smaller variability give better estimates of population parameters. This is because the larger sample includes more of the possible values in the population of interest.

Incorrect. Larger samples with smaller variability give better estimates of population parameters. This is because the larger sample includes more of the possible values in the population of interest.

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Correct. Probability governs the behavior of all of these. Because random samples are selected by means of a random digits table (or computer software), the sampled individuals are chosen according to a probability distribution. Because the sample statistics are computed from that random sample, the statistics are themselves random variables that obey the laws of probability. Most simple random processes (think of flipping a coin or throwing a die) also behave according to the laws of probability. When you have absolutely no idea what might happen, there is *chaos*, which is not governed by the laws of probability.

Incorrect. Probability governs the behavior of all of these. Because random samples are selected by means of a random digits table (or computer software), the sampled individuals are chosen according to a probability distribution. Because the sample statistics are computed from that random sample, the statistics are themselves random variables that obey the laws of probability. Most simple random processes (think of flipping a coin or throwing a die) also behave according to the laws of probability. When you have absolutely no idea what might happen, there is* chaos*, which is not governed by the laws of probability.

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