with o² = 1000(psi)². A random sample of 12 specimens has a mean compressive strength of x = 3250 psi. a. Construct a 95% two-sided confidence interval on mean compressive strength. b. Construct a 99% two-sided confidence interval on mean compressive strength. Compare the width of this confidence interval with the width of the one found in part (a). 8.1.9 WP Suppose that in Exercise 8.1.8 it is desired to estimate the compressive strength with an error that is less than 15 psi at 99% confidence. What sample size is required? 8.1.7 WP A manufacturer produces piston rings for an automo- bile engine. It is known that ring diameter is normally distributed with σ = 0.001 millimeters. A random sample of 15 rings has a mean diameter of x = 74.036 millimeters. a. Construct a 99% two-sided confidence interval on the mean piston ring diameter. b. Construct a 99% lower-confidence bound on the mean piston ring diameter. Compare the lower bound of this confi- dence interval with the one in part (a). 8.1.8 WP VS A civil engineer is analyzing the compressive strength of concrete. Compressive strength is normally distributed

with o² = 1000(psi)². A random sample of 12 specimens has a mean compressive strength of x = 3250 psi. a. Construct a 95% two-sided confidence interval on mean compressive strength. b. Construct a 99% two-sided confidence interval on mean compressive strength. Compare the width of this confidence interval with the width of the one found in part (a). 8.1.9 WP Suppose that in Exercise 8.1.8 it is desired to estimate the compressive strength with an error that is less than 15 psi at 99% confidence. What sample size is required? 8.1.7 WP A manufacturer produces piston rings for an automo- bile engine. It is known that ring diameter is normally distributed with σ = 0.001 millimeters. A random sample of 15 rings has a mean diameter of x = 74.036 millimeters. a. Construct a 99% two-sided confidence interval on the mean piston ring diameter. b. Construct a 99% lower-confidence bound on the mean piston ring diameter. Compare the lower bound of this confi- dence interval with the one in part (a). 8.1.8 WP VS A civil engineer is analyzing the compressive strength of concrete. Compressive strength is normally distributed

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018

18th Edition

ISBN:9780079039897

Author:Carter

Publisher:Carter

Chapter10: Statistics

Section10.5: Comparing Sets Of Data

Problem 14PPS

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