School

Diablo Valley College **We aren't endorsed by this school

Course

MATH 142

Subject

Statistics

Date

Aug 31, 2023

Pages

5

Uploaded by MajorDiscoveryRhinoceros3 on coursehero.com

Question 1
1 / 1 pts
A researcher wanted to know how many cars in their city were yellow. Their
sample found a sample proportion of �^ = 0.32 with a margin of error of
3%. Find a 95% confidence interval for the number of yellow cars in their
city.
HINT: you do not need your calculator to find the interval. Just use the +/- like
with the polling example.
Correct!
(0.29, 0.35)
(0.32, 0.35)
(0.317, 0.323)
(0.02, 0.62)
Question 2
1 / 1 pts
A deli owner thought she was being cheated on the size of her meat
deliveries. She took a sample over the period of a week and found a sample
mean of 16.7 pounds with a margin of error of 2.4 pounds. Find a 95%
confidence interval for what her deliveries weigh.
(15, 18.4)
(16.7, 19.1)
(14.42, 18.98

Correct!
(14.3, 19.1)
Question 3
1 / 1 pts
Which of these is the meaning of a confidence interval?
It's an interval of values for the different samples we might take.
It's an interval of time in which we confidently stand by our results.
Correct!
It's an interval we're pretty confident contains the population parameter.
It's an interval we're pretty confident contains the sample statistic.
Question 4
3 / 3 pts
Suppose a survey of 36 DVC students found the mean cost of their textbooks
was $213.06, with sample standard deviation $18.40. To find a 95%
confidence interval for the mean cost of textbooks for all DVC students,
A.
What calculator command should you use? ["", "", "",
""]
B.
What is the interval you found? (206.83, 219.29)
C.
Which is the correct interpretation? ["", "", "",
""]
Answer 1:

Correct!
T-Interval
Answer 2:
Correct!
(206.83, 219.29)
Answer 3:
Correct!
We are 95% confident the population mean is in the interval we found.
Question 5
3 / 3 pts
Suppose a random sample of 400 college freshman found 95 who were
business majors. Find a 95% confidence interval for the proportion of all
freshman at this college who are business majors.
A.
What calculator command should you use? ["", "", "",
""]
B.
What is the interval you found? ["", "", "", ""]
C.
What is the interpretation of the interval? We are 95% confident the
population proportion of business majors is in the interval we found.
Answer 1:
Correct!
1-PropZInt
Answer 2:
Correct!
(0.1958, 0.2792)
Answer 3:
Correct!
We are 95% confident the population proportion of business majors is in the
interval we found.

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