AA C&C Unit 1 Test REVIEW - Descriptive & Inferential Statistics

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What is the empirical rule (68-95-99.7%)?

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The empirical rule states that for a normal distribution: 68% of data falls within one standard deviation of the mean, 95% falls within two standard deviations, and 99.7% falls within three standard deviations.

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How do you calculate the probability of a value in a normal distribution?

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To calculate the probability of a value in a normal distribution, use the z-score formula: z = (X - μ) / σ, where X is the value, μ is the mean, and σ is the standard deviation.

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What does a z-score represent?

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A z-score represents the number of standard deviations a data point is from the mean. It indicates how unusual or typical a value is in a distribution.

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What is a normal distribution?

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A normal distribution is a symmetric, bell-shaped distribution where most of the observations cluster around the central peak, and probabilities for values further away from the mean taper off equally in both directions.

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What is standard deviation?

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Standard deviation is a measure of the amount of variation or dispersion in a set of values. A low standard deviation indicates that the values tend to be close to the mean, while a high standard deviation indicates that the values are spread out over a wider range.

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What is a population in statistics?

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A population is the entire group of individuals or instances about whom we hope to learn. It includes all the people or objects on which data is collected.

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What is a sample in statistics?

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A sample is a subset of a population selected for observation and analysis. It is used to make inferences about the population as a whole.

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What is a Cluster Random Sample?

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A Cluster Random Sample is a sampling method where the population is divided into clusters (groups), and entire clusters are randomly selected to be included in the sample.

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What is a Simple Random Sample?

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A Simple Random Sample is a sampling method where each member of the population has an equal chance of being selected, ensuring that the sample is representative of the population.

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What is a Stratified Random Sample?

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A Stratified Random Sample is a sampling method where the population is divided into subgroups (strata) that share similar characteristics, and random samples are taken from each stratum.