A civil engineer is analyzing the compressive strength of concrete. Compressive strength isnormally distributed with o? = 1000 (psi)?. A random sample of 12 specimens has a meancompressive strength of X = 3250 psi.1. *Construct a 95% two-sided confidence interval on mean compressive strength.2. *Construct a 99% two-sided confidence interval on mean compressive strength. Comparethe width of this confidence interval with the width of the one found in part (1).

Given : A civil engineer is analyzing the compressive strength of concrete . Compressive strength…

Answered: A civil engineer is analyzing the…

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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A researcher wants to estimate the mean blood cholesterol level of young men ages 15-25 with a 94.35% confidence interval. The blood cholesterol level of young men follows a Normal distribution with standard deviation σσ = 50 mg/dl. How large a sample would the researcher need to take to estimate the mean blood cholesterol to within 15 mg/dl?
The average American consumes 86 liters of alcohol per year. Does the average college student consume a different amount of alcohol per year? A researcher surveyed 10 randomly selected college students and found that they averaged 62.3 liters of alcohol consumed per year with a standard deviation of 22 liters. What can be concluded at the the αα = 0.01 level of significance? For this study, we should use (t-test for population mean, or z-test for population proportion) The null and alternative hypotheses would be: H0: (symbol) (symbol) _____ H1: (symbol) (symbol) _____ The test statistic (symbol) = _____ (please show your answer to 3 decimal places.) The p-value = _____ (Please show your answer to 4 decimal places.) The p-value is (symbol) αα Based on this, we should (fail to reject, reject, accept) the null hypothesis. Thus, the final conclusion is that ... The data suggest the populaton mean is significantly different from 86 at αα = 0.01,…
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 3 points with 99% confidence assuming s = 12.5 based on earlier studies? Suppose the doctor would be content with 90% confidence. How does the decrease in confidence affect the sample size required? E Click the icon to view a partial table of critical values. A 99% confidence level requires subjects. (Round up to the nearest subject.) Tutoring Help me solve this Get more help- Clear all Check answer MacBook Pro ** esc G Search or type URL @ # $ % & 7 8. delete 1 2 3 4 Q W E R Y P 11 G H J K
A researcher wants to estimate the mean blood cholesterol level of young men ages 15-25 with a 93.66% confidence interval. The blood cholesterol level of young men follows a Normal distribution with standard deviation σσ = 35 mg/dl. How large a sample would the researcher need to take to estimate the mean blood cholesterol to within 11 mg/dl?
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 4 points with 99% confidence assuming s = 18.7 based on earlier studies? Suppose the doctor would be content with 90% confidence. How does the decrease in confidence affect the sample size required? A Click the icon to view a partial table of critical values. A 99% confidence level requires subjects. (Round up to the nearest subject.)
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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 = 14.8 based on earlier studies? Suppose the doctor would be content with 90% confidence. How does the decrease in confidence affect the sample size required? Click the icon to view a partial table of critical values. A 99% confidence level requires subjects. (Round up to the nearest subject.)
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