Mr. Rogers - AP Statistics Objectives

Unit Plan Practice Test Practice Test Answers

AP Statistics Test Errors and Hypothesis Testing

  1. For a two tailed test with a p=.02, What is the area under the curve associated with p in one of the tails? Area = 0.01
  2. If a confidence interval is tripled, what is the effect on the margin of error? tripled
  3. If the sample size is increased by a factor of 16, what is the effect on the margin of error? 1/4 times original ME
  4. If the confidence level is changed from 90% to 95% what is the effect on the margin of error? (1.96 / 1.64) times ME or a 19% increase in ME
  5. What conditions must be met in order to use a t-test? SRS, population approximately normally distributed
  6. For a given test of statistical significance alpha = .02 and the p-value = .025. What can you conclude? There is not a statistically significant reason to reject the null hypothesis
  7. Juan obtains a p-value = .018 in his significance test. How should he interpret it? There is an 1.8% probability of getting a value of the test statistic as extreme or more extreme than the one obtained.
  8. A two tailed quality assurance test has an alpha = 5%. What is the probability of a type I error?  5%
  9. Which hypothesis is assumed to be true when evaluating the probability of a type I error?  the null hypothesis
  10. What is the sum of the probability of a type I and type II error for a given set of circumstances? Unknown
  11. What is the sum of the probability of a type II error and power for a given set of circumstances? 1.00
  12. When is a pooled t-test used? When the standard deviations of the 2 samples are considered to be equal
  13. In the American justice system, the presumption of innocence until proven guilty can be called the _________________. null hypothesis
  14. For a hypothesis test beta = 10%. What is the power of the test? 90%
  15. Martha plans a survey and wants a margin of error of 2% with a confidence level of 95%. What is the minimum sample size she should use? n = 2401
  16. Based on a survey of 1600 people, Bob finds that 60% will vote for the purple party. Construct a 95% confidence interval for the data.

    CI = 0.6 1.96 [ .6 (1-.6))/ 1600]^0.5 or .6 0.24

  17. Based on sample of 1000, SC voters vote purple 45% of the time while based on a sample of 1200 voters, GA voters vote purple 49% of the time. Construct a 90% confidence interval for the difference between the two groups. (- 0.075 to -0.0049)
  18. A sample of Martha's coconuts has an average weight of 1.3 lb with a sample size = 12 and s = 4. A sample of Bob's coconuts has an average weight of 1.5 lb with a sample size = 10 and s = 3. Are Bob's coconuts bigger than Martha's? p = 44.7%
  19. Create a 80% confidence interval for the difference between Bob's and Martha's coconuts. (-2.18 to 1.78)
  20. What does the central limit theorem tell us about the effects of sample size on the sampling distribution? As sample size increases, the sampling distribution narrows and looks more like a normal distribution
  21. What 2 conditions must be true to use the normal approximation of the binomial? np >= 10, n(1-p) >= 10