Term
| What is statistical inference the process of? |
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Definition
it's the process of making estimates and testing claims about the characteristics of a population.
2 areas: estimation and hypothesis testing. |
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Term
| What is hypothesis testing? |
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Definition
| the testing of claims about population parameters. |
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Term
| What are point estimates? |
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Definition
single (sample) values used to estimate population parameters. The formula used to compute the point estimate is called the estimator.
for example, sample mean is an estimator. The value generated by the sample mean calculation is called the point estimate of the mean. |
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Term
| How are confidence intervals normally constructed? |
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Definition
in general confidence intervals take on the following form:
point estimate +- (reliability factor times standard error) |
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Term
| What are the desirable properties of an estimator: |
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Definition
- unbiasedness; expected value of the estimator is equal to the parameter you are trying to estimate
- efficiency: variance of sampling distribution is smaller than all other unbiased estimators of the parameter you are trying to estimate.
- consistency: accuracy increases as sample size increases
BLUE |
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Term
| What is the shape of the t-distribution and when should it be used? |
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Definition
bell-shaped symmetrical about its mean.
use when constructing confidence intervals based on small samples (n < 30) from populations with unknown variance and a normal, or approximately normal distribution.
Level of significance of a t-test corresponds to the one-tailed probabilities, p, that head the columns in the t-table. |
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Term
| Formula for constructing a confidence interval for the population mean based on a given confidence level: |
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Definition
| sample mean +- zα/2 times σ / (square root of n) |
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