E- Statistics

Question 1
Read the below scenario and then answer the questions that follow.
The Ancestry Society of North Carolina is compiling records so they can learn
about the history of African Americans in North Carolina from 1820 to 1980. They
have compiled records of all 15,125 gravestones in cemeteries across all 15
counties. They want to choose a sample of 600 records to check their accuracy
by visiting the actual gravestones.
a) Using the hat method explain how they could gather a simple random sample
of 600 gravestones to visit.
b) Explain why it would be better to take a sample 40 gravestones from all 15
counties.
c) For what population could they make inference about after gathering and
examining the sample?
Question 2
Read the below scenario and then answer the questions that follow.
Part 1
Amazon claims that if you are a prime member, 85% of your packages will arrive
within two business days. You have decided that you want to know if this claim is
true. You take a simple random sample of 25 students at your school and 19 of
the students claim that their packages arrived within two business days of
ordering.
a. What is the population proportion? What is the sample proportion? Please use
correct symbols in your answer.
Population Proportion Symbol:
Population Proportion:
Sample Proportion Symbol:
Sample Proportion:
b. Create a bar graph below that would exaggerate the findings from part a. You
want the reader to think that Amazon is not holding up to its claim.
Please give your graph an eye catching title that would make someone mistrust
Amazon.
TITLE:
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Part 2
You decide that you want to make sure your estimate from part a is correct. You
go out and gather 10 simple random samples of 25 people in your school and
calculate the proportion of students within each sample whose Amazon
packages arrive within two business days of ordering.
The proportion of customers that receive their packages within two days of
ordering are given below.
0.70, 0.75, 0.6, 0.95, 0.90, 0.73, 0.87, 0.86, 0.92, 0.97
a. Explain why all of the sample proportions are not the same.
b. Find the average of all 10 proportions above.
c. Compare this to the sample proportion you found in a of part 1. Are they the
same or different?
Sample Proportion from Part 1: _________________
Sample Proportion from Part a: _________________
d. Find the margin of error for the 10 samples.
e. How can we decrease the margin of error?
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f. Based on Amazon’s claim of 85% and your sample proportions, do you
believe Amazon’s claim? Explain.
Question 3
Researchers in New Zealand conducted an experiment with college students at
Victoria University to determine the effects of in- class tablet use on student
learning. All participants were asked to attend to attend a class and take their
tablet.
● 25 students used the tablets solely to take notes.
● 25 students were assigned to do non classroom related activities such as
web browsing and checking social media during class.
● The final 25 students were asked to take notes on notebook paper.
● When the students entered the classroom they picked a piece of paper out
of the hat. 25 said paper, 25 stated notes on laptop, and 25 stated web
browsing on laptop.
● Students were to work in class based on what they picked out of the hat.
● At the end of the class, all students took a comprehension test to
determine how much they learned from class.
● The result was that students who were multitasking on the computer had
13% less comprehension than the students who were taking notes on the
laptop or by paper.
a. What was the treatment? (There are two)
Treatment 1: ________________________________
Treatment 2: ________________________________
b. What was the control group?
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c. What were researchers comparing in this experiment?
d. Can we establish cause and effect here? Why or why not?
e. For what population could we make inference?
f. Explain why this is an experiment and not an observational study