MILQUESTION 2Problem 2:The time to complete a task on a project is normally distributed with mean of 75 hours and a standard deviation of 5 hours.a. What is the probability that a task will be completed in less than 60 hours?b. What is the third quartile of the time to complete tasks?c. A random sample of 25 project tasks are selected, what is the probability that average completion time is greater than 80hours.

Answered: QUESTION 2 Problem 2: The time to…

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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c4. Manufacturer A's television picture tubes have a mean lifespan of 7.23 years and a standard deviation of 0.72 years; while those of manufacturer B have a mean duration of 6.46 years and a standard deviation of 0.44 years. What is the probability that a random sample of 38 kinescopes from manufacturer A will have a mean lifespan that is 1 year less than the mean lifespan in a sample of 42 kinescopes from manufacturer B? Round your answer to four decimal places after the period. Select one: a. The probability is 0.9745 b. None of the above c. The probability is 0.9554 d. The probability is 0.9841
1. Scores on a certain nationwide college entrance examination follow a normal distribution with a mean of 500 and a standard deviation of 100. Find the probability that a student will score
The rate of return for firms on the stock market is normally distributed with a 7.5% average rate of return (the mean) with a standard deviation of 2.5%. A What proportion of firms will earn a return between 4% and 8%? B To the nearest percent find the probability of a firm earning 3% or less per year. If there are 1000 firms listed on the stock market, then how many firms earn a return of less than 3% a year? C To the nearest percent, find the probability of a firm earning 8% return in a year. if there are still 1000 firms listed on the stock markeet then how many firms will earn a return of 8% or higher? D What rate of return would put a firm in the top 20%?
18. On average, a banana will last 6.3 days from the time it is purchased in the store to the time it is too rotten to eat. Is the mean time to spoil greater if the banana is hung from the ceiling? The data show results of an experiment with 15 bananas that are hung from the ceiling. Assume that that distribution of the population is normal. 5.4, 8.2, 7.8, 6.8, 6.4, 8.3, 5, 7.5, 7, 5.3, 6.9, 8.8, 8.9, 9, 8.5 What can be concluded at the the αα = 0.05 level of significance level of significance? For this study, we should use T- Test, Z test The null and alternative hypotheses would be: H0: P or U, <>=, H1: P or U, <>=, The test statistic T,Z = (please show your answer to 3 decimal places.) The p-value = (Please show your answer to 4 decimal places.) The p-value is <> αα Based on this, we should the null hypothesis. Thus, the final conclusion is that ... The data suggest that the population…
3. The finish times for marathon runners during a race are normally distributed with a mean of 195 minutes and a standard deviation of 25 minutes. What is the probability that a runner will complete the marathon within 180 minutes?
Suppose the mean income of firms in the industry for a year is $25 million with a standard deviation of $9 million. If incomes for the industry are distributed normally, what is the probability that a randomly selected firm will earn less than $34 million? Round your answer to four decimal places
Suppose the mean income of firms in the industry for a year is 25 million dollars with a standard deviation of 7 million dollars. If incomes for the industry are distributed normally, what is the probability that a randomly selected firm will earn less than 40 million dollars? Round your answer to four decimal places.
Suppose that the walking step lengths of adults are normally distributed with a mean of 2.4 feet and a standard deviation of 0.3 feet. A sample of 34 step lengths is taken. Find the probability that the mean of the sample taken is more than 2.5 feet. Your answer should be from the cumulative normal distribution table.
2. Does helping another person affect the helper's life satisfaction? To find out, a researcher randomly sampled 64 people and asked each of them to help one other person that day. At the end of the day, each participant completed a standardized measure of life satisfaction. The mean score for the sample was 51.60. In the general population, the mean score on this measure is 50 and the standard deviation is 6. Test the hypothesis that helping affects life satisfaction (a = .05, two-tailed). You don't have to outline all 5 steps of hypothesis testing, but specify the properties of the comparison distribution, the critical value of the test statistic for rejecting the null hypothesis, the obtained test statistic, and the final decision. What are the lower and upper confidence limits for the 95% confidence interval of the mean life satisfaction of people who have helped someone else that day? Compute the standardized effect size.
Suppose that the number of points scored in a game comes from a normal population with an average of 12 points and a standard deviation of 9 points. Estimate the chance that the average points scored in ten randomly selected games will exceed 14.2 points. A. 0.4034 B. 0.0073 C. 0.2198 D. 0.2297
Suppose the heights of students in a class follows normal distribution. The mean is 66 inches and the standard deviation is 5 What is the probability that a randomly selected student height is above 69 inches? What is the probability that the height will fall in between 45-54 inches? Which of the following intermediate step is involved in finding probability that a randomly selected student height is more than 70 inches?
Suppose that the average number of hurricanes is 32 per year with a standard deviation of 2.8 and follow a normal distribution. What is the probability that we will have more than 31 hurricanes this year in a decimal form?

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