Answers edited by VSH

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• If the mean time between in-flight aircraft engine shutdowns is 12500 operating hours, the 90th percentile of waiting times to the next shutdown will be?
  
• At a football game, a researcher randomly asks 100 people to name their favorite sport. Is this a biased sample?
  
• A linear chain is made of 20 identical links. Each link can be made in 7 different colors. How many # physically # different chains are there?
  
• Of 238 employees selected randomly from one company, 10.08% of them commute by carpooling. How do you construct a 90% confidence interval for the true percentage of all employees of the company who carpool?
  
• Assume that z scores are normally distributed with a mean of 0 and a standard deviation of 1. If #P(z>c)=.0559#, what is #c#?
  
• A federal report stated that 88% of children under 18 were covered by health insurance in 2000. How large a sample is needed to estimate the true proportion of covered children with 90% confidence with a confidence interval of .05 wide?
  
• Question #5110a
  
• A committee of 5 is to be selected from a group of 6 men and 9 women. If the selection is made randomly, what is the probability that the committee consists of 3 men and 2 women?
  
• Where will a prediction interval or a confidence interval be narrower: near the mean or further from the mean?
  
• What is the difference between VAR.S function and VAR.P function on Microsoft Excel?
  
• How do confidence levels compare to significance levels?
  
• A manager states that, in 2003, on average a small and medium firm charged at least $ 3,000 on its business credit card. What are the appropriate null and alternative hypotheses?
  
• The mean IQ score of statistics professors is less than 119. The significance level is 0.05. What is the null hypothesis (H0) and alternative hypothesis (H1)?
  
• ? Find the percent of a standard normal model found in the region : #z<1.13#
  
• How to find calculate this?
  
• The correlation coefficient of a linear fit between two variables #X# and #Y# is #-1#. I want to know, does the line containing the points for the strong negative correlation always have a slope of negative one? Thanks :)
  
• Question #1889a
  
• What is a discrete probability distribution? What two conditions determine a probability distribution?
  
• A biology quiz consists of 14 multiple-choice questions. Nine must be answered correctly to receive a passing grade. If each question has 4 possible answers,what is the probability that a student who guesses at random will pass?
  
• What is the median, mode, mean, and range of 17, 19, 22, 22, 27, 31, 35, 37, 45, 98?