Suppose a random sample of 2100 people reveals that 1870 of them have cell phones. A)...

Suppose a random sample of 2100 people reveals that 1870 of them have cell phones.

A) Construct a 95% confidence interval for the true proportion of people who have cell phones.

B) Repeat for confidence level 99%

Expert Solution

Here, = 1870 / 2100

= 0.8904

A) Z value for 95% confidence interval = 1.96

The 95% confidence interval is = z* (1- )/n

= 0.8904 0.013

= ( 0.876 , 0.904 )

B) Z value for 99% confidence interval = 2.58

The 99% confidence interval is = z* (1- )/n

= 0.8904 0.018

= ( 0.872 , 0.907 )

orchestra answered 3 years ago

4. Suppose a random sample of 2100 people reveals that 1870 of them have cell phones. a. Construct...

4. Suppose a random sample of 2100 people reveals that 1870 of them have cell phones. a. Construct a 95% confidence interval for the true proportion of people who have cell phones. b. Repeat for confidence level 99%.

On the island of Lilliput, a sample random sample of 500 people reveals that 450 of...

On the island of Lilliput, a sample random sample of 500 people reveals that 450 of them prefer to open their egg on the small end. On the island of Blefuscu, a sample random sample of 400 people reveals that 345 of them prefer to open their egg on the small end. Assuming that Lilliputians and Blefuscuans are equally likely to open their egg on the small end, what is the probability of selecting samples of these sizes with the...

Suppose that in a simple random sample of 100 people, 69 of them believe the Seahawks...

Suppose that in a simple random sample of 100 people, 69 of them believe the Seahawks will win the Superbowl this year. We want to determine if the proportion of people in the population who believes this is less than 0.75. Choose the appropriate concluding statement. a. The sample data do not provide evidence that the proportion of people who believe the Seahawks will win the SuperBowl is less than 0.75. b. The sample data provide evidence that the proportion...

Suppose we have 4 students and we take their phones then return the phones to them...

Suppose we have 4 students and we take their phones then return the phones to them randomly. Let X be the number of students who receive their own phone. Create a probability distribution chart for X.

In a random sample of 9 cell phones, the mean full retail price was $522.20 and...

In a random sample of 9 cell phones, the mean full retail price was $522.20 and the standard deviation was $191.00. Further research suggests that the population mean is $425.49. Does the t-value for the original sample fall between -t 0.95 and t 0.95? Assume that the population of full retail prices for cell phones is normally distributed. The t-value of t=____ does does not??? fall between -t 0.95 and t 0.95 because t 0.95=___ (Round to two decimal places...

In a random sample of twelve cell phones, the mean full retail price was $496.50 and...

In a random sample of twelve cell phones, the mean full retail price was $496.50 and the standard deviation was $187.00. Assume the population is normally distributed and use the t-distribution to find the margin of error and construct a 90% confidence interval for the population mean μ. Interpret the results. Identify the margin of error. ? dollars cell phones square dollars (Round to one decimal place as needed.)

(a) Suppose that a random sample of 387 television ads in the United Kingdom reveals that...

(a) Suppose that a random sample of 387 television ads in the United Kingdom reveals that 131 of these ads use humor. Find a point estimate of and a 95 percent confidence interval for the proportion of all U.K. television ads that use humor. (Round your answers to 3 decimal places.) pˆp^ = [ ] The 95 percent confidence interval is [ , ]. (b) Suppose a random sample of 493 television ads in the United States reveals that 134...

[3] In a random sample of 13 cell phones, the mean full retail price was $745...

[3] In a random sample of 13 cell phones, the mean full retail price was $745 with standard deviation of $152. Assume the population is normally distributed. Find the margin of error and the 95% confidence interval for the population mean.

In a random sample of 315 people 80 of them were smokers. Based on the above...

In a random sample of 315 people 80 of them were smokers. Based on the above sample test whether the data provides sufficient evidence that the proportion of smokers is different from 20%, using 2% significance level. What type of error could you have made in your decision?

Hypothesis: If people are frequently interrupted by messages on their cell phones while working on an...

Hypothesis: If people are frequently interrupted by messages on their cell phones while working on an assignment, then it will take them much longer to complete the assignment beyond the time it took to read and reply to the messages. Design an experiment that would test this hypothesis. In your description, identify the independent variable (including the experimental and control conditions) and the dependent variable.

Question