Which of the following correctly describes how the width of a confidence interval for a population mean changes when the population standard deviation is known?O There is no change if just the sample size increases.O The interval widens if the sample size stays the same and confidence level decreases.O The interval narrows if the sample size increases and confidence level stays the same.O The interval narrows if the sample size decreases and confidence level stays the same.O The interval widens if the sample size increases and the confidence level stays the same.

The interval narrows if the sample size increases and confidence level stays the same. Explanation:…

Answered: Which of the following correctly…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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12 Jane's instructor asks her to build a 95% confidence interval with a margin of error of $30. What should the minimum sample size be in order for Jane to attain the required MOE? For planning value Jane uses the standard deviation from her original sample. a 264 b 244 c 226 d 209
The distribution of study times for first year students follows a Normal distribution with standard deviation σ = 78 minutes. Suppose a sample of 452 students found that the mean study time for these students was x¯= 192 minutes per week. Use this to find a 95% confidence interval to estimate the mean study time for all students. We are 95% confident that the mean study time for first year students is between _____minutes and _____ minutes
Moviegoers The average "moviegoer" sees 8.5 movies a year. A moviegoer is defined as a person who sees at least one movie in a theater in a 12-month period. A random sample of 47 moviegoers from a large university revealed that the average number of movies seen per person was 9.1. The population standard deviation is 3.2 movies. At the 0.10 level of significance, can it be concluded that this represents a difference from the national average? Part 1 of 5 State the hypotheses and identify the claim with the correct hypothesis. H: u = 8.5 not claim H, : u + 8.5 claim This hypothesis test is a two-tailed test. Part 2 of 5 Find the critical value(s). Round the answer to at least two decimal places. If there is more than one critical value, separate them with commas. Critical value(s):-1.645, 1.645 Part: 2 /5 Part 3 of 5 Compute the test value. Always round z score values to at least two decimal places.
K You want to buy a washing machine, and a salesperson tells you that the mean repair costs for Model A and Model B are equal. You research the repair costs. The mean repair cost of 25 Model A washing machines is $212. Assume the population standard deviation is $20. The mean repair cost of 27 Model B washing machines is $228. Assume the population standard deviation is $21. At a=0.01, can you reject the salesperson's claim? Assume the samples are random and independent, and the populations are normally distributed. Complete parts (a) through (e). (a) Identify the claim and state Ho and Ha What is the claim? OA. The mean repair costs for Model A and Model B are equal. OB. The mean repair cost for Model A is less than Model B. OC. The mean repair costs for Model A and Model B are different. OD. The mean repair cost for Model A is greater than Model B. Let u₁ be the mean repair cost for Model A and let ₂ be the mean repair cost for Model B. What are Ho and H₂? OA. Ho: H1 H2 Ha H₁242 OD.…
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Moviegoers The average "moviegoer" sees 8.5 movies a year. A moviegoer is defined as a person who sees at least one movie in a theater in a 12-month period.A random sample of 42 moviegoers from a large university revealed that the average number of movies seen per person was 9.6. The population standard deviation is 3.2 movies. At the 0.10 level of significance, can it be concluded that this represents a difference from the national average? (a)State the hypotheses and identify the claim with the correct hypothesis. (b)Find the critical value(s). (c)Compute the test value. (d)Make the decision. (e)Summarize the results.
Bike sale The bicycle shop in Exercise 52 will be offer-ing 2 specially priced children’s models at a sidewalk sale. The basic model will sell for $120 and the deluxemodel for $150. Past experience indicates that sales ofthe basic model will have a mean of 5.4 bikes with astandard deviation of 1.2, and sales of the deluxe modelwill have a mean of 3.2 bikes with a standard deviationof 0.8 bikes. The cost of setting up for the sidewalk saleis $200.a) Define random variables and use them to express thebicycle shop’s net income.b) What’s the mean of the net income?c) What’s the standard deviation of the net income?d) Do you need to make any assumptions in calculatingthe mean? How about the standard deviation?
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Moviegoers The average "moviegoer" sees 8.5 movies a year. A moviegoer is defined as a person who sees at least one movie in a theater in a 12-month period. A random sample of 42 moviegoers from a large university revealed that the average number of movies seen per person was 10.2. The population standard deviation is 3.2 movies. At the 0.01 level of significance, can it be concluded that this represents a difference from the national average? Part 1 of 5 State the hypotheses and identify the claim with the correct hypothesis. Hotu = 85 Part: 1/5 not claim H₁ 8.5 claim This hypothesis test is a two-tailed ▼test. Part 2 of 5 ▼ ▼ Find the critical value(s). Round the answer to at least two decimal places. If there is more than one critical value, separate them with commas. Critical value(s): X 0.0.... + 8分民图〗b. E
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True or false? If the original x distribution has a relatively small standard deviation, the confidence interval for ? will be relatively short. a. False. As ? decreases, E decreases, resulting in a longer confidence interval. b. True. As ? decreases, E increases, resulting in a shorter confidence interval. c. True. As ? decreases, E decreases, resulting in a shorter confidence interval. e. False. As ? decreases, E increases, resulting in a longer confidence interval.

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