100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Previously searched by you
Previously searched by you
logo
MATH 225N Week 6 Assignment: Understanding Confidence Intervals – Excel $76.49
Add to cart
Quickly navigate to
Preview
  2.  
  3. Chamberlain College Of Nursng
  4.  
  5. MATH 225N Week 6 Assignment: Understanding Confidence Interval (MATH225N)

Exam (elaborations)

MATH 225N Week 6 Assignment: Understanding Confidence Intervals – Excel
 1 purchase

MATH 225N Week 6 Assignment: Understanding Confidence Intervals – Excel questions and all correct answers

Preview 2 out of 11  pages

Document information

  • January 13, 2021
  • 11
  • 2020/2021
  • Exam (elaborations)
  • Questions & answers

Subjects

  • math 255n
  • math255n
  • math 225n week 6 assignment understanding confidence intervals
  • math225n week 6 assignment understanding confidence intervals
  • math 225n week 6 assignment answers

Written for

All documents for this subject (1)

Seller

avatar-seller
bettergrades19

Reviews received

Content preview

MATH 225N Week 6 Assignment: Understanding Confidence
Intervals – Excel
Calculate a Confidence Interval for a Proportion - Excel
Question
In a random sample of 350 attendees of a minor league baseball game, 184 said that they bought
food from the concession stand. Create a 95% confidence interval for the proportion of fans who
bought food from the concession stand. Use Excel to create the confidence interval, rounding to
four decimal places.

Yes that's right. Keep it up!


(0.4734, 0.5780)

Answer Explanation


Correct answers:


 0.4734
 0.5780


The confidence interval for the unknown population
proportion p is (p̂ −z⋆p̂ (1−p̂ )n‾‾‾‾‾‾‾‾‾√,p̂ −z⋆p̂ (1−p̂ )n‾‾‾‾‾‾‾‾‾√). The confidence interval can
be calculated using Excel.

1. Identify α. Click on cell A1 and enter =1−0.95 and press ENTER.

2. Thus, α=0.05. Enter the number of successes, x=184, and sample size, n=350, in the Excel
sheet in cells A2 and A3. To find the proportion of successes, p̂ , click on cell A4 and
enter =A2/A3 and press ENTER.

3. Thus, p̂ ≈0.5257. Use the NORM.S.INV function in Excel to find z⋆. Click on cell A5,
enter =NORM.S.INV(1−A1/2), and press ENTER.

4. The answer for z⋆, rounded to two decimal places, is z⋆≈1.96. To calculate the standard
error, p̂ (1−p̂ )n‾‾‾‾‾‾‾‾‾√, click on cell A6 and enter =SQRT(A4∗(1−A4)/A3) and press ENTER.

, 5. The answer for the standard error, rounded to four decimal places,
is p̂ (1−p̂ )n‾‾‾‾‾‾‾‾‾√≈0.0267. To calculate the margin of error, z⋆p̂ (1−p̂ )n‾‾‾‾‾‾‾‾‾√, click on cell
A7 and enter =A5*A6 and press ENTER.

6. The answer for the margin of error, rounded to four decimal places,
is z⋆p̂ (1−p̂ )n‾‾‾‾‾‾‾‾‾√≈0.0523. The confidence interval for the population proportion has a
lower limit of A4−A7=0.4734 and an upper limit of A4+A7=0.5780. Thus, the 95%confidence
interval for the population proportion of fans who bought food from the concession stand, based
on this sample, is approximately (0.4734, 0.5780).

Calculate a Confidence Interval for a Proportion - Excel
Question
Alison, the owner of a regional chain of pizza stores, is trying to decide whether to add calzones
to the menu. She conducts a survey of 700 people in the region and asks whether they would
order calzones if they were on the menu. 46 people responded “yes.” Create a 90% confidence
interval for the proportion of people in the region who would order calzones if they were on the
menu.Round your answer to four decimal places.

Correct! You nailed it.


(0.0503, 0.0811)
90% confidence interval is (0.0503, 0.0811)

Explanation:
Given that x = 46 and n = 700
Sample proprotion p^ = x/n = 46/700= 0.0657
we know that z critical for 90% level is 1.645

Confidence interval = p^±z∗((1−p^)∗p^
)/n =0.0657±1.645∗((1−0.0657)∗0.0657)/700 =0.0657±1.645∗0.009364 =(0.0503,0.0811)
Calculate a Confidence Interval for the Mean, population standard deviation known -
Excel
Question
A company wants to determine a confidence interval for the average CPU time of its
teleprocessing transactions. A sample of 70 random transactions in milliseconds is given below.
Assume that the transaction times follow a normal distribution with a standard deviation
of 600 milliseconds. Use Excel to determine a 98% confidence interval for the average CPU time
in milliseconds. Round your answers to the nearest integer and use ascending order.
Great work! That's correct.

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

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

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

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 bettergrades19. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for $76.49. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

68175 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 15 years now

Start selling
$76.49  1x  sold
  • (0)
Add to cart
Added