Other
BES220 Semester Test 2 2020
- Course
- Institution
Test paper for Semester Test 2 2020
[Show more]
Seller
Follow
katdjordjevic143
Content preview
14/10/2020 Semester test 2Semester test 2
Click on a question number to see how your answers were marked and, where
available, full solutions.
Question Number
Question 1
Question 2
Question 3
Question 4
Performance Summary
Exam Name: Semester test 2
Session ID: 0448463074
Student's Name: K (Katarina) Djordjevic (011cdd57506642ec949f60ac53aa58da)
Exam Start: Wed Oct 14 2020 07:30:19
Exam Stop: Wed Oct 14 2020 08:53:56
Time Spent: 1:23:36
Question 1
Answer the following multiple-choice questions.
1.
Quality control engineers are testing two di erent light bulbs, designed to have a
lifetime of more than 450 hours. 97 of the first type of light bulbs were tested and
0.35% of them have a lifetime of more than 450 hours. 144 of the second type of light
bulbs were tested and 0.57% of them have a lifetime of more than 450 hours. The
engineers want to conduct a hypothesis test to test if there is a di erence in the quality
of the bulbs.
https://numbas.up.ac.za/run_attempt/87074?resource_link_id=_2040073_1 1/11
, 14/10/2020 Semester test 2
What is the Standard Error for the hypothesis test?
0.0636 0.0413 0.0656 0.0484
2 marks
2.
According to a report on sleep deprivation by the Centers for Disease Control and
Prevention, the proportion of California residents who reported insu icient rest or
sleep during each of the preceding 30 days is 0.079%, while this proportion is 0.091%
for Oregon residents. These data are based on simple random samples of 11112
California and 4686 Oregon residents. Calculate a 95% confidence interval for the
di erence between the proportions of Californians and Oregonians who are sleep
deprived and interpret it in the context of the data. Assume that all conditions are
satisfied.
(0.00,0.95) (0.0024,0.0216) (0.079,0.091)
(-0.0216,-0.0024)
2 marks
3.
Approximately 0.09% of engineering students in South Africa are women. To test
whether our university di ers significantly from this national average, we take a
random sample of 40 engineering students at our university and find that 9 are female.
Calculate the appropriate test statistic to determine whether our university di ers
significantly from the national rate.
2.9835 2.0447 0.0452 -2.0447 0.225
2 marks
https://numbas.up.ac.za/run_attempt/87074?resource_link_id=_2040073_1 2/11
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller katdjordjevic143. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $4.26. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67096 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now