30. A research and development engineer is preparing a report for the board of directors on thebattery life of a new cell phone they have produced. At a 95% confidence level, he has found thatthe battery life is 3.2+1.0 days. He wants to adjust his findings so that the margin of error is assmall as nossible. Which of the following will produce the smallest margin of error?Decrease the confidence level to 90%Increase the confidence level to 99%Increase the confidence level to 100%. This will assure that there is no margin of error.Take a new sample from the population using a smaller sample size

Answer: Take a new sample from the population using a larger sample size.

Answered: 30. A research and development engineer…

Advanced Engineering Mathematics

10th Edition

ISBN:9780470458365

Author:Erwin Kreyszig

Publisher:Erwin Kreyszig

Chapter2: Second-order Linear Odes

Section: Chapter Questions

Problem 1RQ

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The waiting time for patients at a health clinic follows a normaldistribution with a mean of 15 minutes and a population standard deviation of 5 minutes.The public health office sampled 50 patients and found that the mean waiting time was 14.25 minutes. (a) What is the value of the test statistic? (Rounded to three decimal places.)(b) Write the hypotheses if you think the true mean is less than 15 minutes.(c) If α = 10%, can you reject the null hypothesis?
A doctor wants to estimate the mean HDL cholesterol of all 20- to 29-year-old females. How many subjects are needed to estimate the mean HDL cholesterol within 2 points with 99% confidence assuming s=16.5 based on earlier studies? Suppose the doctor would be content with 95% confidence. How does the decrease in confidence affect the sample size required?
A doctor wants to estimate the HDL cholesterol of all 20- to 29-year-old females. How many subjects are needed to estimate the HDL cholesterol within 2 points with 99% confidence assuming a= 16.3? Suppose the doctor would be content with 90% confidence. How does the decrease in confidence affect the sample size required? A 99% confidence level requires subjects. (Round up to the nearest whole number as needed.)
A sample of 20 items provides a sample standard deviation of 4.
A sample of 22 picture tubes is tested and the current needed to achieve the brightness is measured. The data yields I = 123.09, s = 20.3. Given a = 0.05, find the upper (larger) endpoint of a 100(1 – a)% confidence interval based on the given data. answer correct to 2 decimals
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Suppose we are able to use a normal model. In order to construct a 99% Confidence Interval, we have to find the margin of error (ME), and we can use the following formula: 2.579*SE, where SE is computed with the image that's attached to this problem. Using SE = 0.049, find ME for the 99% Confidence Interval. Round your answer to 3 decimal places.
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When 40 people used the Weight Watchers dies for one year, their mean weight loss was 3.0 lb and the standard deviation was 4.9 lb. Use a 0.01 significance level to test the claim that the mean weight loss is greater than 0. (Show the solution) A. The null hypothesis is i. The mean weight loss is equal to 0. ii. The mean weight loss is not equal to 0. iii. The mean weight loss is greater than 0. iv. The mean weight loss is less than 0. B. The computed t-test statistic is i. 4.468 ii. 4.977 iii. 3.872 iv. 3.391 C. The critical/tabular t-test statistic is i. 2.426 ii. 1.684 iii. 1.685 iv. 2.423 D. Decision rule: i. Do not reject the null hypothesis. ii. Reject the null hypothesis. E. The final conclusion is i. The mean weight loss is not equal to 0 therefore Weight Watchers is effective. ii. The mean weight loss is less than 0 therefore Weight Watchers is not effective. iii. The mean weight loss is equal to 0 therefore Weight Watchers…
Mrs. Gallas wanted to estimate the average weight of an Oreo cookie to determine if theaverage weight was less than advertised. She selected a random sample of 30 cookies andfound the weight of each cookie (in grams). The mean weight was = 11.1921 grams with astandard deviation of sx = 0.0817 grams. Make a 95% confidence interval to estimate the truemean weight of an Oreo. 1. What is the formula for calculating the standard deviation of the sampling distribution of x? 2.What condition must be met to use this formula? Has it been met?
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