a What proportion of rings will have inside diameters exceeding 10075

# A what proportion of rings will have inside diameters

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(a) What proportion of rings will have inside diameters exceeding 10.075 centimeters? (b) What is the probability that a piston ring will have an inside diameter between 9.97 and 10.03 centimeters? (c) Below what value of inside diameter will 15% of the piston rings fall? Q4: The yield of a chemical process is being studied. From previous experience yield is known to be normally distributed and σ = 3. The past five days of plant operation have resulted in the following percent yields: 91.6, 88.75, 90.8, 89.95, and 91.3. Find a 95% confidence interval on the true mean yield. Q5: The life in hours of a 75-watt light bulb is known to be normally distributed with σ = 25 hours. A random sample of 20 bulbs has a mean life 𝑥̅ = 1014 of hours. Construct a 95% confidence interval on the mean life. Suppose that in we wanted to be 95% confident
MATH 411 Probability& Statistics Homework 5 Dr. Hany Nasr Hassan that the error in estimating the mean life is less than 5 hours. What sample size should be used? Q6: The brightness of a television picture tube can be evaluated by measuring the amount of current required to achieve a particular brightness level. A sample of 10 tubes results in 𝑥̅ = 317.2 and 𝑠 = 15.7 . Find (in microamps) a 99% confi dence interval on mean current required. Q7: A particular brand of diet margarine was analyzed to determine the level of polyunsaturated fatty acid (in percentages). A sample of six packages resulted in the following data: 16.8, 17.2, 17.4, 16.9, 16.5, 17.1. Find a 99% confidence interval on t he mean μ .

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