SOC 381 A chimpanzee named Sarah was the subject
Question # 00342603
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Updated on: 07/21/2016 01:39 AM Due on: 07/21/2016
1. A chimpanzee named Sarah was the subject in a study of whether chimpanzees can solve
problems. Sarah was shown 30-second videos of a human actor struggling with one of several
problems (for example, not able to reach bananas hanging from the ceiling). Then Sarah was
shown two photographs, one that depicted a solution to the problem (like stepping onto a box)
and one that did not match that scenario. Researchers watched Sarah select one of the photos,
and they kept track of whether Sarah chose the correct photo depicting a solution to the
problem. Sarah chose the correct photo in 7 of 8 scenarios that she was presented.
a. We want to run a test of significance to determine if Sarah understands how to solve
problems and will thus pick the photo of the correct solution more often that what
would be done randomly. Write out the null and alternative hypotheses for this in either
words or symbols.
(problem 8. continued)
b. You conducted a test of significance using simulation and get the following null
distribution. (Note this null distribution uses only 100 simulated samples and not the
usual 1000 or 10,000.) Based on the null distribution, what is the p-value for the test?
c. Complete this sentence describing what the p-value means. If Sarah doesn’t understand
how to solve problems and is just guessing at which picture to select, the probability she
would …
d. Based on your p-value, do you have strong evidence that Sarah understands how to solve
problems similar to those she was presented.
2. Suppose I am conducting a test of significance where the null hypothesis is my cat Grayce will
pick the correct cancer specimen 25% of the time and the alternative hypothesis is that she will
pick the cancer specimen at a rate different than 25%. (Note: this is a two-sided alternative.) I
end up with a p-value of 0.02. I also construct 90% and 95% confidence intervals from my data.
What will be true about my confidence interval?
a)
b)
c)
d)
Both the 90% and the 95% intervals will contain 0.25.
Neither the 90% nor the 95% intervals will contain 0.25.
The 90% interval will contain 0.25, but the 95% interval will not contain 0.25.
The 90% interval will not contain 0.25, but the 95% interval will contain 0.25.
problems. Sarah was shown 30-second videos of a human actor struggling with one of several
problems (for example, not able to reach bananas hanging from the ceiling). Then Sarah was
shown two photographs, one that depicted a solution to the problem (like stepping onto a box)
and one that did not match that scenario. Researchers watched Sarah select one of the photos,
and they kept track of whether Sarah chose the correct photo depicting a solution to the
problem. Sarah chose the correct photo in 7 of 8 scenarios that she was presented.
a. We want to run a test of significance to determine if Sarah understands how to solve
problems and will thus pick the photo of the correct solution more often that what
would be done randomly. Write out the null and alternative hypotheses for this in either
words or symbols.
(problem 8. continued)
b. You conducted a test of significance using simulation and get the following null
distribution. (Note this null distribution uses only 100 simulated samples and not the
usual 1000 or 10,000.) Based on the null distribution, what is the p-value for the test?
c. Complete this sentence describing what the p-value means. If Sarah doesn’t understand
how to solve problems and is just guessing at which picture to select, the probability she
would …
d. Based on your p-value, do you have strong evidence that Sarah understands how to solve
problems similar to those she was presented.
2. Suppose I am conducting a test of significance where the null hypothesis is my cat Grayce will
pick the correct cancer specimen 25% of the time and the alternative hypothesis is that she will
pick the cancer specimen at a rate different than 25%. (Note: this is a two-sided alternative.) I
end up with a p-value of 0.02. I also construct 90% and 95% confidence intervals from my data.
What will be true about my confidence interval?
a)
b)
c)
d)
Both the 90% and the 95% intervals will contain 0.25.
Neither the 90% nor the 95% intervals will contain 0.25.
The 90% interval will contain 0.25, but the 95% interval will not contain 0.25.
The 90% interval will not contain 0.25, but the 95% interval will contain 0.25.
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Solution: SOC 381 A chimpanzee named Sarah was the subject