What is a 95 percent confidence interval?most common statistical standard

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What is a census?Researchers who enjoy complete access to their populations of interest are working with a census (as opposed to a sample).

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What is the central limit theorem?For random sampling with a large sample size n, the sampling distribution of the sample mean y is approximately a normal distribution. This holds no matter what the shape of the population distribution. The result also applies to proportions.

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What are degrees of freedom?the number of independent observations used to calculate a statistic

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What are inferential statistics?Provide predictions about a population, based on data from a sample of that population.

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What are the mean and standard error of y?Consider a random sample of size n from a population having mean μ and standard error σ. The sampling distribution of y gives the probabilities for the possible values of y. It has mean μ and standard error σy = σ/sqrt(n).
What is the mean of a probability distribution?The expected value of a realization of the distribution, E(y). For a discrete variable, the mean, μ = ΣyP(y).
What is the normal distribution?a distribution defined by a mathematical formula and the graph of which has a symmetrical, bell shape; in which the mean, mode, and median coincide; and in which a fixed proportion of observations lies between the mean and any distance from the mean measured in terms of the standard deviation

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What is the normal distribution?A symmetric, bell shaped distribution characterized by its mean, μ, and standard deviation, σ. The probability within any particular number of standard deviations of μ is the same for all normal distributions. This probability equals 0.68 within 1 standard deviation, .095 within 2 standard deviations, and 0.997 within 3 standard deviations.
What is a population?all the cases or observations covered by a hypothesis; all the units of analysis to which a hypothesis applies

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What is a population parameter?the incidence of a characteristic or an attribute in a population (not a sample)

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What is probability?With a random sample or randomized experiment, the probability an observation has a particular outcome is the proportion of times that outcome would occur in a very long sequence of observations.

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What is a random sample?A set of observations randomly drawn from the population of interest. Random selection ensures the sample is representative of the population of interest.

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What is random sampling error?extent to which a sample statistic differs BY CHANCE from a population parameter

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What is random selection?Random selection occurs when every member of the population has an equal chance of being included in the sample.

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Define range.the distance between the highest and lowest values or the range of categories into which observations fall

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What is response bias?Response bias occurs when the subject gives an incorrect response (perhaps lying), or the question wording or the way the researcher asks a question is confusing or misleading.

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What is a sample?a subset of observations or cases drawn from a specified population

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What is a sample proportion?the number of cases falling into one category of the variable divided by the number of cases in the sample

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What is a sample statistic?the estimator of a population characteristic or attribute that is calculated from sample data

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What is a sampling distribution?The probability distribution that specifies probabilities for the possible values the statistic can take.
What is a sampling frame?The population from which a sample is drawn. Ideally it is the same as the total population of interest to a study.

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What is selection bias?Selection bias occurs when non-random processes - often unknown to the researcher - cause differences between test (treatment) group and the control group.

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What is a standard deviation?A measure of dispersion of data points about the mean for interval- and ratio-level data. Standard deviation is equal to the square root of variance, and describes a typical distance from the mean.

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What is a standard error?The standard deviation of the sample distribution of y is called the standard error of y. The standard error of y is denoted by σy.

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What is a standard error?The standard deviation of the sample distribution of y is called the standard error of y. The standard error of y is denoted by σy.
What is the standard normal distribution?The normal distribution with mean μ = 0 and standard deviation σ = 1.
What is standardization?occurs when the numbers in a distribution are transformed into standard units of deviation from the mean of the distribution

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What is the Student's t-distribution?a probability distribution that can be used to make inferences about a population mean when the sample size is small

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What is variance?A measure of dispersion of data points about the mean for interval- and ratio-level data. Variance averages the squared deviations about the mean.

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What is a Z score?the number of standard deviations by which a score deviates from the mean score

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