STAT 330 Chapter 9 – Statistics Study Guide and Practice Material

STAT 330 - Chapter 9 {100%Success}
STAT 330 - Chapter 9
Study online at https://quizlet.com/_hpbnh6

1. Q: What is a point estimate? A single value used to estimate a population para-
meter.

2. Q: What is a confidence interval? An interval estimate that provides a range of plausi-
ble values for a parameter.

3. Q: What is the general form of a con- Estimator ± (critical value)(standard error).
fidence interval?

4. Q: What is the interpretation of a 95% If repeated samples are taken, about 95% of such
confidence interval? intervals will contain the true parameter.

5. Q: What is the standard error of the σ/n.
mean when σ is known?

6. Q: What distribution is used for CI of Normal distribution.
mean when σ is known?

7. Q: What distribution is used for CI of t-distribution with n-1 degrees of freedom.
mean when σ is unknown?

8. Q: What is the CI for μ when σ is un- X̄ ± t(α/2, n-1)(S/n).
known?

9. Q: What is the CI for μ when σ is X̄ ± z(α/2)(σ/n).
known?

10. Q: What is the CI for a population pro- p̂ ± z(α/2)[p̂(1-p̂)/n].
portion p?

11. Q: What is pooled variance in Sp² = [(n1-1)S1² + (n2-1)S2²] / (n1+n2-2).
two-sample t-tests?

12. (X̄1-X̄2) ± t(α/2, n1+n2-2)[Sp²(1/n1+1/n2)].

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