A random sample of size n₁ = 16 is selected from a normal population with a mean of 75and a standard deviation of 8. A second random sample of size n₂ = 9 is taken from anothernormal population with mean 70 and standard deviation 12. Let X₁ and X₂ be the two samplemeans. Find:(a) The probability that X₁ X₂, exceeds 4(b) The probability that 3.5 ≤ X₁ – X₂ ≤ 5.5

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Answered: A random sample of size ₁ = 16 is…

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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Let the random variable x have a normal distribution with a mean value of 70 and a varience of 25. Then find the probability that P (x<80)
Use the Suppose in a local Kindergarten through 12th grade (K -12) school district, 42% of the population favor a charter school for grades K through 5. A simple random sample of 144 is surveyed. nd the mean and the standard deviation of X of B(144, 0.42). Round off to 4 decimal places. b. Now approximate X of B(144, 0.42) using the normal approximation with the random variable Y and the table. Round off to 4 decimal places. Y N( C Find the probability that at most 72 favor a charter school using the normal approximation and the table. Round off to z-values up to 2 decimal places.) P(X 68) P(Y > ~ (Z >) e. Find the probability that exactly 63 favor a charter school using the normal approximation and the table. (Round off to z-values up to 2 decimal places.) P(X = 63) P(
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where appropriate. 1. Experience has shown that the seeds from a certain variety of orchid have a 75% chance of germinating when planted under normal conditions. Suppose n seeds are planted, and let X be the random variable that counts the number of seeds that germinate. (a) What type of random variable is X? Indicate both the type and the appropriate parameters using the "~" notation. Write down the pmf of X, and do not forget to indicate the range of values that x can take on. X ~ px (x) = = (b) What is the minimum value of n so that the probability of at least five of the seeds germinating is at least 90%?
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Executives of a supermarket chain are interested in the amount of time that customers spend in the stores during shopping trips. The mean shopping time, µ, spent by customers at the supermarkets has been reported to be 40 minutes, but executives hire a statistical consultant and ask her to determine whether it can be concluded that u is greater than 40 minutes. To perform her statistical test, the consultant collects a random sample of shopping times at the supermarkets. She computes the mean of these times to be 44 minutes and the standard deviation of the times to be 15 minutes. Based on this information, answer the questions below. What are the null hypothesis (H,) and the alternative hypothesis (H,) that should be used for the test? Hiµ is ? H: p is ? In the context of this test, what is a Type II error? A Type II error is ? fact, u is ? the hypothesis that u is when, in Suppose that the consultant decides not to reject the null hypothesis. What sort of error might she be making?
Assume that women's weights are normally distributed with a mean given by μ=143 lb and a standard deviation given by 29 lb.(a) If 1 woman is randomly selected, find the probabity that her weight is between 113 lb and 172 lb(b) If 3 women are randomly selected, find the probability that they have a mean weight between 113 lb and 172 lb(c) If 73 women are randomly selected, find the probability that they have a mean weight between 113 lb and 172 lb

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