What is the meaning of an alpha region being 0.05?
It is the certainty we have about our evidence
It is the number of times we miss when something is happening
It is the percentage of time we incorrectly reject the null hypothesis
It is the inverse of the Z-score formula
(1 mark each) If I have a population distribute normally with mean of 7 and SD of 16, what are the parameters (ie mean and sd)of the sampling distributions with
N = 3?
N = 7?
N = 13?
N = 160?
(2 marks) Some researchers asked 87 undergraduates how often they give to charity in a given month. If the national average is normally distributed with a mean of 2.3 and a standard deviation of 1.4, what are the mean and standard deviation (ie the parameters) of the sampling distribution of the mean?
(4 marks). Clinical researchers want to know whether a new antidepressant is more effective than current treatments. Assume that duration of treatment is normally distributed with a mean of 18 months and SD of 3.5. In the researchers’ sample of 286 participants, the mean duration of treatment was 15 months. Using the Z-test, is there evidence that the new antidepressant is more effective?
(1 mark). Which of the following examples can be analyzed using the Z test?
a) You find the average number of books per dorm room in Nyland (no standard deviation) and want to compare it to the average number of books per room in Bromley to see if they differ significantly.
b) You germinate 100 seeds and compare the number of seeds that sprouted to the average rate of germination as advertised by the nursery you bought them from
c) With a sample of 100 plants, you find the average yield of tomatoes in pounds. You then compare that mean to the mean yield and standard deviation for tomato plants grown under ideal conditions. You wish to know whether the yield of your plants matches those grown under ideal conditions.
(1 mark) Why do we look up the Z-table when conducting the Z-test?
a) To find the probability of our mean given the null hypothesis
b) To calculate a standard deviation
c) To convert an area into a percentage
d) To standardize our sampling distribution
(1 mark) Which of the following is a difference between the critical region and exact p-value approaches to significance testing?
a) They both return different decisions
b) The critical region approach makes it unnecessary to use a Z-table
c) The calculated statistic will differ by a factor of 1/sqrt(n)
d) The critical region approach is always two-tailed
Which of the following is/are (an) example(s) of a two-tailed alternative hypothesis? (circle all that apply)
a) I want to know if people take longer showers in winter than summer
b) I want to know whether people sleep for different amounts in different seasons
c) I want to know whether house prices are related to natural disasters such as floods
d) I want to know whether people are more resistant to vertigo if they have spent more time hiking in mountains
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