Confidence Interval, Margin of Error & Sample size

You work for a consumer advocate agency and want to find the mean repair cost of a washing machine. As part of your study, you randomly select 45 repair costs and find the mean to be $117.00. The standard deviation is $18.90. Complete parts (a) and (b).
a. Construct a 90% confidence interval for the population mean repair costs.
b. Change the sample size to n = 90. Construct a 90% confidence interval for the population mean repair cost.
Which confidence interval is wider? Explain. Choose the correct answer below.
2. People were polled on how many books they read the previous year. How many subjects are needed to estimate the number of books read the previous year within one book with 95% confidence? Initial survey results indicate that σ = 10.7 books

3. Repair Costs: Microwaves In a random sample of five microwave ovens, the mean repair cost was $80.00 and the standard deviation was $13.00. Assume the variable is normally distributed and use a t-distribution to construct a 90% confidence interval for the population mean µ. What is the margin of error of µ?

Don't use plagiarized sources. Get Your Custom Essay on
Confidence Interval, Margin of Error & Sample size
From $10/Page
Order Essay

4. A researcher wishes to estimate, with 99% confidence, the proportion of adults who have high-speed internet access. Her estimate must be accurate within 5% of the true proportion.

a) Find the minimum sample size needed, using a prior study that found that 38% of the respondents said they have high-speed internet access.

b) No preliminary estimate is available. Find the minimum sample size needed.

5. An election poll reported that a candidate had an approval rating of 31% with a margin of error E of 2%. Construct a confidence interval for the proportion of adults who approve of the candidate.

6. Find the margin of error for the given values of c, s and n.

c = 0.95, s = 3.1, n = 36

7. Construct the 98% confidence interval for the population mean µ.

c = 0.98, x-bar = 16.2, s = 8.0 and n = 70

8. Construct the indicated confidence interval for the population mean µ using (a) a t-distribution. (b) If you had incorrectly used a normal distribution, which interval would be wider?

c = 0.99, x-bar = 14.2, s = 2.0, n = 9

9. Construct the indicated confidence interval for the population mean µ using a t-distribution.

c = 0.80, x-bar = 108, s = 10, n = 13

10. A researcher wishes to estimate, with 90% confidence, the percentage of adults who support abolishing the penny. His estimate must be accurate within 5% of the true proportion.

a) Find the minimum sample size needed, using a prior study that found that 38% of the respondents said they support abolishing the penny.

See attached file. Solution Summary
The solution provides step by step method for the calculation of confidence interval, margin of error and sample size. Formula for the calculation and Interpretations of the results are also included. Interactive excel sheet is included. The user can edit the inputs and obtain the complete results for a new set of data.

To continue with the answer check on mycoursewriter.com/

Calculate the price
Make an order in advance and get the best price
Pages (550 words)
$0.00
*Price with a welcome 20% discount applied.
Pro tip: If you want to save more money and pay the lowest price, you need to set a more extended deadline.
We know how difficult it is to be a student these days. That's why our prices are one of the most affordable on the market, and there are no hidden fees.

Instead, we offer bonuses, discounts, and free services to make your experience outstanding.
How it works
Receive a 100% original paper that will pass Turnitin from a top essay writing service
step 1
Upload your instructions
Fill out the order form and provide paper details. You can even attach screenshots or add additional instructions later. If something is not clear or missing, the writer will contact you for clarification.
Pro service tips
How to get the most out of your experience with My Course Writer
One writer throughout the entire course
If you like the writer, you can hire them again. Just copy & paste their ID on the order form ("Preferred Writer's ID" field). This way, your vocabulary will be uniform, and the writer will be aware of your needs.
The same paper from different writers
You can order essay or any other work from two different writers to choose the best one or give another version to a friend. This can be done through the add-on "Same paper from another writer."
Copy of sources used by the writer
Our college essay writers work with ScienceDirect and other databases. They can send you articles or materials used in PDF or through screenshots. Just tick the "Copy of sources" field on the order form.
Testimonials
See why 10k+ students have chosen us as their sole writing assistance provider
Check out the latest reviews and opinions submitted by real customers worldwide and make an informed decision.
Communications
Thank you for your hard work; I enjoyed reading the essay and appreciate your writing.
Customer 452483, July 18th, 2021
Nursing
Excellent writing !! Definitely I will use your services again... Thank you.
Customer 452487, August 22nd, 2021
Other
I appreciate the help.
Customer 452567, March 18th, 2022
Psychology
Thank you so much for all of your hard work & help! It’s perfect! Appreciate it!!
Customer 452483, September 11th, 2021
Nursing
Excellent! Thank you.
Customer 452487, October 16th, 2021
Microbiology
Perfect! Thank you guys for all of your great help! :)
Customer 452483, August 23rd, 2021
Education
Thank you for your help
Customer 452555, February 16th, 2022
Mathematics
Thank you so much!
Customer 452483, July 26th, 2021
Communications
EXCELLENT JOB!!! VERY PLEASED :)
Customer 452483, July 5th, 2021
English 101
Amazing thank you!
Customer 452615, August 1st, 2022
Microbiology
Thank you so much! I appreciate what you do and all of the great help you've given me!
Customer 452483, September 6th, 2021
Healthcare Writing & Communications
You guys are awesome! Appreciate all of your hard work! Thank you.
Customer 452483, October 15th, 2021
1159
Customer reviews in total
96%
Current satisfaction rate
2 pages
Average paper length
47%
Customers referred by a friend
OUR GIFT TO YOU
20% OFF your first order
Use a coupon 20OFF and enjoy expert help with any task at the most affordable price.
Claim my 20% OFF Order in Chat
Open chat
Chat with us Live Here
Get in Touch with Our Live Chat Agents via WhatsApp on +1(346) 416-0954. Get Unlimited Access to Answers on Any Queries With Your Paper.