Learn Without Walls

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Module 6 Quiz

15 Questions • 70% to Pass

1What is the general form of a confidence interval?

2A 95% CI is (45, 55). The point estimate is:

3When should you use the t-distribution instead of z for CIs for means?

4For a sample of n = 25, what are the degrees of freedom?

5The formula for CI for a mean is x̄ ± t*(s/√n). What is s/√n called?

6Sample: n=100, x̄=50, s=15. For 95% CI (z*=1.96), what is the margin of error?

7The success-failure condition for proportion CIs is:

8For a 95% CI for a proportion, what is z*?

9n=200, p̂=0.45. What is the standard error for a proportion CI?

10What happens to the margin of error if you increase sample size?

11Sample size formula for means: n = (z*σ/E)². To estimate within E=5, σ=20, z*=1.96, what is n?

12When estimating a proportion with no prior info, what value should you use for p̂?

13If you want to cut margin of error in half, by what factor must n increase?

14Which confidence level produces the WIDEST interval?

15A 95% CI for μ is (48, 52). Which is the correct interpretation?