D E F K M P Assume X is normal random varaible with mean 50 and sandard deviation 10. P(X>30)= P(40
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Q: Assume that adults have IQ scores that are normally distributed with μ=105 and a standard deviation…
A: Assume that adults have IQ scores that are normally distributed with μ=105 and a standard deviation…
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Q: Assume that adults have IQ scores that are normally distributed with a mean of μ=100 and a standard…
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Q: The percent of fat calories that a person in America consumes each day is normally distributed with…
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Q: An IQ test is designed so that the mean is 100 and the standard deviation is 18 for the population…
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Q: Assume that adults have IQ scores that are normally distributed with a mean of μ=105 and a standard…
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Q: Assume that adults have IQ scores that are normally distributed with a mean of μ=100 and a standard…
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Q: Assume that the sample is a simple random sample obtained from a normally distributed population of…
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- An IQ test is designed so that the mean is 100 and the standard deviation is 10 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 99% confidence that the sample mean is within 8 IQ points of the true mean. Assume that σ=10 and determine the required sample size.A population has a mean of 200 and a standard deviation of 90. Suppose a simple random sample of size 125 is selected and is used to estimate μ. Use z-table. a. What is the probability that the sample mean will be within 18 of the population mean (to 4 decimals)? b. What is the probability that the sample mean will be within 16 of the population mean (to 4 decimals)?For the population of one town, the number of siblings, x, is a random variable whose relative frequency histogram has a reverse J-shape. The mean number of siblings is 1.3 and the standard deviation is 1.5. Let x denote the mean number of siblings for a random sample of size 32. Determine whether the distribution of x is normal or approximately normal and find its mean and standard deviation.
- Assume that final exam scores in a given course are approximately normally distributed with a mean of 75 and a standard deviation of 10 points. In a class of 200 students, how many would you expect to fail the exam (i.e., score less than 60) (note: scores can only be approximately normally distributed, because the minimum score is 0, but this should not alter the answer, given how large the mean is relative to the standard deviation).Suppose the masses of a batch of 2000 potatoes have a mean of 60 grams with a standard deviation of 8 grams. Assuming the weights have a normal distribution, predict the number of potatoes that would have masses between 45 and 55 grams. Sketch the distribution curve, shade the required probability, and show horizontal scales the population parameters and the z-scores. Solve the problemSuppose that an airport reports that the average time it takes for a person to get through security in 25 minutes. Assume the variable is approximately normally distributed with a standard deviation of 4.5 minutes. If 102 people were selected at random, how many would be expected to make it through security in less than 20 minutes? Approximately _________would make it through in less than 20 minutes.
- Chebyshev's Theorem states that for any distribution of numerical data, at least 1-1/k? of the numbers lie within The percent of numbers between 88 and 112 is at least %. k standard deviations of the mean. (Round to the nearest hundredth as needed.) In a certain distribution of numbers, the mean is 100, with a standard deviation of 6. Use Chebyshev's Theorem to tell what percent of the numbers are between 88 and 112.4. Let X be a random variable representing dividend yield of Australian bank stocks. We may assume that X has a normal distribution with standard deviation = 2.4%. A random sample of 19 Australian bank stocks has a sample mean of = 8.71%. For the entire Australian stock market, the mean dividend yield is = 5.9%. Do these data indicate that the dividend yield of all Australian bank stocks is higher than 5.9% ? Use Q=.05. Are the data statistically significant at the given level of significance? Based on your answers, will you reject or fail to reject the null hypothesis? A. The p-value is less than the level of significance and so the data are not statistically significant. Thus, we reject the null hypothesis. B. The p-value is less than the level of significance and so the data are statistically significant. Thus, we fail to reject the null hypothesis. C. The p-value is greater than the level of significance and so the data are statistically significant. Thus, we fail to reject the…The percent of fat calories that a person in America consumes each day is normally distributed with a mean of about 36 and a standard deviation of 10. Suppose that one individual is randomly chosen. Let X=percent of fat calories. Round all answers to 4 decimal places if where possible a. What is the distribution of X? X N( b. Find the probability that a randomly selected fat calorie percent is more than 40. c. Find the minimum number for the lower quarter of percent of fat calories.
- Q3: The effective life of a component used in a jet-turbine aircraft engine is a random variable with mean 5000 hours and standard deviation 40 hours. The distribution of effective life is fairly close to a normal component that increases the mean life to 5030 hours and decreases the standard deviation to 30 hours. distribution. The engine manufacturer introduces an improvement into the manufacturing process for this Suppose that a random sample of n₁ = 16 components is selected from the "Old" process and a random sample of n₂ = 25 components is selected from the "Improved" process. What is the probability that difference in the two-sample means that the old and improved processes can be regarded as independent populations. 5 X₂X₁ is at least 15 hours? AssumeThe average length of time for students to register in the second semester at a certain university has been 55 minutes. A new registration procedure is being tested. If random samples of 16 students have an average of 50 minutes with standard deviation of 12 minutes under system, can you conclude that the new system is faster than the old one? Assume that the average length of time is normally distributed. Use ά = 0.05.Suppose that the duration of a particular type of criminal trial is known to be normally distributed with a mean of 20 days and a standard deviation of 5 days. Let X be the number of days for a randomly selected trial. Round all answers to 4 decimal places where possible.