StatTutor Lesson - Accurate Confidence Intervals for Comparing Proportions

true
Stat Tutor
true
true
You have completed 0 question sequences out of 7.
Accurate confidence intervals for comparing proportions
Video Player is loading.
Current Time 0:00
Duration 0:00
Loaded: 0%
Stream Type LIVE
Remaining Time 0:00
 
1x
    • Chapters
    • descriptions off, selected

      Question 1

      122

      Question 1.

      When is “plus four” confidence interval recommended for estimating p1 - p2?

      A.
      B.
      C.

      Incorrect. Using the “plus four” confidence interval to estimate p1 - p2 improves the accuracy of the level of confidence when the sample sizes are not very large.
      Correct. Using the “plus four” confidence interval to estimate p1 - p2 improves the accuracy of the level of confidence when the sample sizes are not very large.
      Incorrect. Try again.
      2

      Question 2

      167

      Question 2.

      How large do the sample sizes need to be in order to estimate p1 - p2 with a "plus four" confidence interval?

      A.
      B.
      C.

      Incorrect. Both sample sizes need to be at least 5 in order to estimate p1 - p2 with a "plus four" confidence interval.
      Correct. Both sample sizes need to be at least 5 in order to estimate p1 - p2 with a "plus four" confidence interval.
      Incorrect. Try again.
      2

      Questions 3-5

      225

      Question 3.

      What is the explanatory variable?

      A.
      B.
      C.
      D.

      Incorrect. The two treatments were: duct tape and freezing; the explanatory variable is type of wart removal (or whether duct tape or feezing was used to get rid of a wart.)
      Correct. The two treatments were: duct tape and freezing; the explanatory variable is type of wart removal (or whether duct tape or feezing was used to get rid of a wart.)
      Incorrect. Try again.
      2

      Question 6

      264

      Question 6.

      True or false: We use a "plus four" interval to estimate p1 - p2 because the sample sizes are so small.

      A.
      B.

      Incorrect. The sample sizes are 22 and 26 which are too small for a large sample confidence interval for p1 - p2.
      Correct. The sample sizes are 22 and 26 which are too small for a large sample confidence interval for p1 - p2.
      Incorrect. Try again.
      2

      Question 7

      317

      Question 7.

      Are the sample sizes large enough to use a "plus four" confidence interval to estimate p1 - p2?

      A.
      B.

      Incorrect. The sample sizes are 26 and 25; since both are bigger than 5, they are big enough.
      Correct. The sample sizes are 26 and 25; since both are bigger than 5, they are big enough.
      Incorrect. Try again.
      2

      Question 8

      369

      Question 8.

      What is the name for the value 0.233?

      A.
      B.

      Incorrect. The value of 0.233 is the margin of error.
      Correct. The value of 0.233 is the margin of error.
      Incorrect. Try again.
      2

      Question 9

      403

      Question 9.

      In context, what is p1 - p2 for this study?

      A.
      B.

      Incorrect. p1 - p2 is a parameter and thus must be stated as such. It is the difference between two population proportions. p1 = the proportion of all patients with warts who get rid of them using duct tape and p2 = the proportion of all patients with warts who get rid of them using freezing.
      Correct. p1 - p2 is a parameter and thus must be stated as such. It is the difference between two population proportions. p1 = the proportion of all patients with warts who get rid of them using duct tape and p2 = the proportion of all patients with warts who get rid of them using freezing.
      Incorrect. Try again.
      2