She conducted the experiment and performed a significance test, which resulted in a P -value of 0.77.
Which statement describes the correct conclusion?(A) Because the P -value is greater than 0.5, there is evidence that μ (^) N > μ (^) C.
(B) Because the P- value is low, there is evidence that μ (^) N = μ (^) C.
(C) Because the P- value is high, there is evidence that μ (^) N = μ (^) C.
(D) Because the P- value is low, there is insufficient evidence to say μ (^) N = μ (^) C.
(E) Because the P- value is high, there is insufficient evidence to say μ (^) N > μ (^) C.
A company is planning an experiment to determine whether a new insect repellent formula is more
effective than its old formula. The company plans to randomly select one arm on each volunteer to be
sprayed with the new formula, and the other arm will be sprayed with the old formula. Each arm will
be put into an aquarium full of mosquitos for five minutes. The researchers will count the number of
bites on each arm. Which of the following would be the most appropriate inference technique?
(A) A z -test for a difference in proportions
(B) A t -test for a difference in means
(C) A confidence interval for a difference in proportions
(D) A one-sample t -test for matched pairs
(E) Two confidence intervals, one for each insecticide formula
- A polling organization conducted a survey of 850 randomly selected U.S. adults one year ago and
asked whether they were happy with the state of their community. Seventy-eight percent said yes. This
year the organization polled 925 randomly selected U.S. adults, and 81% answered yes to the same
question. The pollsters will conduct a significance test to see if they have evidence that the
percentage of U.S. adults who are happy with their community has changed. What should the standard
deviation used in the denominator of the test statistic z be?