A study at Harvard found that 44% of their students binge drink. You are at Princeton...
A study at Harvard found that 44% of their students binge drink. You are at Princeton doing a similar study. How many people do you need to interview to get your interval width down to 10 percentage points? For a 95% CI, what is that sample size?
Homework Answers
for an interval width of 10 %, margin of error =10/2 =5% ~ 0.05
| here margin of error E = | 0.0500 | |
| for95% CI crtiical Z = | 1.96 | |
| estimated proportion=p= | 0.4400 | |
| required sample size n = | p*(1-p)*(z/E)2= | 379 |
Add Answer to:
A study at Harvard found that 44% of their students binge drink.
You are at Princeton...
A company with a large fleet of cars wants to study the gasoline usage. They check...
A company with a large fleet of cars wants to study the gasoline usage. They check the gasoline usage for 50 company trips chosen at random, finding a mean of 25.02 mpg. Based on the past experience, they believe the standard deviation of the general gasoline usage is 4.83 mpg. Which kind of confidence intervals is appropriate to use here, z-interval or t-interval? Please use R to find the critical value they need when constructing a 95% CI. Please. Use...
You are interested in estimating the proportion of students at OSU who plan to study abroad. ...
You are interested in estimating the proportion of students at OSU who plan to study abroad. You construct a 95% confidence interval based on a survey of a random sample of 125 students, and the interval ends up being from 0.109 to 0.243. If you had instead constructed a 99% confidence interval based on the same sample of data, rather than a 95% confidence interval, how would the center of the interval change? A More information is needed in order...
A university dean randomly selected 200 students and found that 102 of them were receiving financial...
A university dean randomly selected 200 students and found that 102 of them were receiving financial aid. a) Calculate the 80% confidence interval for the true rate of students who receive financial aid. Interpret the result. b) Calculate the 90% confidence interval for the true rate of students who do not receive financial aids. Interpret the result. c) How large a sample size needed with 95% confidence to estimate the true rate of students who receive financial aid within 0.05....
The student affairs office of a public university wishes to study absenteeism among students at the...
The student affairs office of a public university wishes to study absenteeism among students at the School of Business during the semester. A random sample of 100 business students reveals the following: •Absenteeism: mean = 9.7 classes & standard deviation = 8.0 classes •48 business studentswere absent more than 5 classes a.Construct a 95% confidence interval estimate of the population mean number of absences for business students during the semester. b.Construct a 90% confidence interval estimate of the population proportion...
You want to estimate the mean IQ for a population of students with a 95% confidence...
You want to estimate the mean IQ for a population of students with a 95% confidence interval. Assume that the population standard deviation is known to be 15. If you want your estimate to be within 5 points of the value of the parameter, you will need a sample size of... (Round z to the nearest hundredth.)
23.26 Do our athletes graduate? Return to the study in Exercise 22.19 (page 530), which found...
23.26 Do our athletes graduate? Return to the study in Exercise 22.19 (page 530), which found that 149 of 190 athletes admitted to a large university graduated within 6 years. This did not differ significantly (P=0.0968) from the 82% graduation rate for all students at the university. It may be more informative to give a 95% confidence interval for the graduation rate of athletes. Construct this confidence interval. Is the 82% graduation rate for all students included in your confidence...
1. What effect does raising the level of confidence have on the width of the confidence...
1. What effect does raising the level of confidence have on the width of the confidence interval? 2. What effect does lowering the the sample size have on the width of the confidence interval? 3. What effect does a smaller population standard deviation have on the width of the confidence interval? 4. Which of the following is the best interpretation for a 99% confidence interval? 5. Based on prior studies, you believe the standard deviation of IQ is normally distributed...
1. A study aims to understand the year-to-year changes in small business sales during the winter...
1. A study aims to understand the year-to-year changes in small business sales during the winter holiday period in the US. Researchers randomly sampled 100 small businesses in December 2014 and found that 66 of them had an increase in sales relative to December 2013. a. Find a 95% confidence interval for the proportion of businesses that had an increase in sales Find the sample size needed for the 68% confidence interval to be of the same width as the...
A study aims to understand the year-to-year changes in small business sales during the winter holiday...
A study aims to understand the year-to-year changes in small business sales during the winter holiday period in the US. Researchers randomly sampled 100 small businesses in December 2014 and found that 66 of them had an increase in sales relative to December 2013. a. Find a 95% confidence interval for the proportion of businesses that had an increase in sales. Find the sample size needed for the 68% confidence interval to be of the same width as the 95%...
A study aims to understand the year-to-year changes in small business sales during the winter holiday...
A study aims to understand the year-to-year changes in small business sales during the winter holiday period in the US. Researchers randomly sampled 100 small businesses in December 2014 and found that 66 of them had an increase in sales relative to December 2013. a. Find a 95% confidence interval for the proportion of businesses that had an increase in sales. Find the sample size needed for the 68% confidence interval to be of the same width as the 95%...
A company with a large fleet of cars wants to study the gasoline usage. They check the gasoline usage for 50 company trips chosen at random, finding a mean of 25.02 mpg. Based on the past experience, they believe the standard deviation of the general gasoline usage is 4.83 mpg. Which kind of confidence intervals is appropriate to use here, z-interval or t-interval? Please use R to find the critical value they need when constructing a 95% CI. Please. Use...
You want to estimate the mean IQ for a population of students with a 95% confidence interval. Assume that the population standard deviation is known to be 15. If you want your estimate to be within 5 points of the value of the parameter, you will need a sample size of... (Round z to the nearest hundredth.)
1. What effect does raising the level of confidence have on the width of the confidence interval? 2. What effect does lowering the the sample size have on the width of the confidence interval? 3. What effect does a smaller population standard deviation have on the width of the confidence interval? 4. Which of the following is the best interpretation for a 99% confidence interval? 5. Based on prior studies, you believe the standard deviation of IQ is normally distributed...
1. A study aims to understand the year-to-year changes in small business sales during the winter holiday period in the US. Researchers randomly sampled 100 small businesses in December 2014 and found that 66 of them had an increase in sales relative to December 2013. a. Find a 95% confidence interval for the proportion of businesses that had an increase in sales Find the sample size needed for the 68% confidence interval to be of the same width as the...
A study aims to understand the year-to-year changes in small business sales during the winter holiday period in the US. Researchers randomly sampled 100 small businesses in December 2014 and found that 66 of them had an increase in sales relative to December 2013. a. Find a 95% confidence interval for the proportion of businesses that had an increase in sales. Find the sample size needed for the 68% confidence interval to be of the same width as the 95%...
A study aims to understand the year-to-year changes in small business sales during the winter holiday period in the US. Researchers randomly sampled 100 small businesses in December 2014 and found that 66 of them had an increase in sales relative to December 2013. a. Find a 95% confidence interval for the proportion of businesses that had an increase in sales. Find the sample size needed for the 68% confidence interval to be of the same width as the 95%...
Most questions answered within 3 hours.
-
1- What are 5 general characteristics of Botticelli’s
paintings?
2- Describe 5 important traits of Flemish...
asked 43 minutes ago -
A golfer claims that his average golf score at the course he
plays regularly is less...
asked 57 minutes ago -
On May 1, First Bank perfected a security interest in Debtor’s
inventory. On June 1, Bob...
asked 1 hour ago -
A new kind of typhoid shot is being developed by a medical
research team. The old...
asked 3 hours ago -
Write a chemical equation for these reactions. (Use
the lowest possible whole number coefficients.) Include
states-of-matter...
asked 5 hours ago -
For each of the Z-scores below, determine two probabilities
(show four three decimal places): (1) the...
asked 5 hours ago -
Oxidative phosphorylation is achieved through chemiosmotic
coupling, which turns chemical energy into osmotic potential energy
that...
asked 8 hours ago -
Hollywood Shoes would like to maintain their cash account at a
minimum level of $64,000, but...
asked 8 hours ago -
Proteins CtrA-P, DnaA, and GcrA behave similarly to what
molecule in the Eukaryotic Cell Cycle?
asked 8 hours ago -
TRUE OR FALSE
In case of a competitive tender procedure, in the request for
quotation, the...
asked 8 hours ago -
I am a little behind please provide some explanation, will
provide thumbs up.
This question considers...
asked 8 hours ago -
Let say the utility function as U(X,Y) = lnX + Y. Show that the
marginal rate...
asked 8 hours ago