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PSYC 3003 Chapter 8.1.
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PSYC 3003 Chapter 8.1.
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PSYC 3003 Chapter 8.1An interval estimate - correct answer-is an interval of numbers that is believed to contain the
actual value of the parameter. -> Confidence intervals.
Statistical inference methods - correct answer-use probability calculations that assume that
the data were gathered with a random sample or a randomized experiment (see Chap. 4).
Probability Calculations - correct answer-refer to a sampling distribution of a statistic, which
is often approximately a normal distribution.
Two types of statistical inference methods - correct answer-(i) estimation of population
parameters (Chap. 8) and
(ii) testing hypotheses about the parameter values (Chap. 9).
The estimation method - correct answer-constructs an interval of numbers, called a
confidence interval, which represents a set of highly plausible values for the unknown
parameter value.
A point estimate - correct answer-is a single number that is a "best guess" for the parameter.
-> Use the most appropriate (i.e., best) sample statistic here.
Properties of Point Estimators
Property 1: - correct answer-A good point estimator has a sampling distribution that is
centered at (i.e., whose mean is) the parameter it tries to estimate
An estimator with this property is unbiased.
The sample mean 𝑥 ̅ is an unbiased estimator of the population mean. - correct answer-The
sample proportion is an unbiased estimator of the population proportion p.
Properties of Point Estimators Property 2: - correct answer-A good point estimator has a
small standard deviation compared to other possible estimators.
An estimator with this property is efficient (this term is not used in the text).
This tells us the estimator tends to fall closer than other estimates to the parameter. - correct
answer-The sample mean has a smaller standard deviation than the sample median when
estimating the center of a normal distribution.
A point estimate by itself is not sufficient because it doesn't tell us how close the estimate is
likely to be to the parameter - correct answer-The margin of error measures how accurate
the point estimate is likely to be in estimating a parameter.
Interval Estimation - correct answer-is a multiple of the standard deviation of the sampling
distribution of the point estimate, such as 1.96 × (standard deviation), when the sampling
distribution is a normal distribution.
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