The distribution of piston diameters is normally distributed with mean μ inches and standard deviation 5 inches. Engineer Dan takes a sample of 25 pistons from the manufacturing assembly line. Let X1, X2, ..., X25 denote these observations which are iid (independently & identically distributed).
a.) What is the probability that X-bar, the sample mean of Dan's 25 observations, is within 1 inch of the population mean μ?
b.) Suppose engineer Jane decides to take a sample of 30 observations. Let Y1, Y2, ..., Y30 denote these observations which are also iid. Jane computes the probability that her sample mean is with 1 inch of the population mean μ. Without doing any calculations, do you think this probability will be smaller or bigger than that for Dan's sample mean? Explain your answer clearly.
The distribution of piston diameters is normally distributed with mean μ inches and standard deviation 5...
The sample mean X is to be used to estimate the mean μ ofa normal distribution with standard deviation 4 inches. How large a sample should be taken in order that, with 90% probability, the estimate will be in error by at most one-half inch? n. 1 The sample mean X is to be used to estimate the mean μ ofa normal distribution with standard deviation 4 inches. How large a sample should be taken in order that, with 90%...
A machining operation produces bearings with diameters that are normally distributed with mean 5.0005 inches and standard deviation 0.0010 inch. Specifications require the bearing diameters to lie in the interval 5.000 ± 0.0020 inches. Those outside the interval are considered scrap and must be remachined. What should the mean diameter, in inches, be in order to minimize the fraction of bearings that are scrapped? = ______________ in
distributed, with a mean of 1.31 inches and a standard deviation of 0.04 inch A random sample The dameter of a brand of ping-pong ball is approximately normally balls is seledted Complete parts (a) through (d) of 16 ping-pong is a. What is the sampling distribution of the mean? O A. Because the population dameter of Ping Pong bals s approxdmahely nomaly distrbuted, the sampling distbution of samples of 16 will be the uniform distribution OB. Because the population dan...
A normally distributed population has a mean of 500 and a standard deviation of 80. a. Determine the probability that a random sample of size 25 selected from this population will have a sample mean less than 463 . b. Determine the probability that a random sample of size 16 selected from the population will have a sample mean greater than or equal to 538. A company makes windows for use in homes and commercial buildings. The standards for glass...
Company ABC claims that they produces cans whose diameters are normally distributed with a population mean of 2 inches and a population standard deviation of 0.06 inch. A customer wants to check if the mean diameter of the cans is different than 2 inches. He takes a random sample of nine samples and finds a sample mean of 1.95 inches. Use a significance level of α = 0.07 to perform a hypothesis test using p value approach. Answer key: Two...
Let the random variable X follow a normal distribution with a mean of μ and a standard deviation of σ. Let X 1 be the mean of a sample of 36 observations randomly chosen from this population, and X 2 be the mean of a sample of 25 observations randomly chosen from the same population. a) How are X 1 and X 2 distributed? Write down the form of the density function and the corresponding parameters. b) Evaluate the statement:...
Heights of men are normally distributed with a mean of 69.0 inches and a standard deviation of 2.8 inches. What is the probability that a randomly selected group of 16 men have a mean height greater than 71 inches.
2. Consider a large population with mean μ and known standard deviation σ = 5. There are two independent simple random samples of this population, one with n 150, and the other with n2 = 400, Denote the two sample means by , and X2, respectively. Let Cli and C12 be the usual 95% confidence intervals, constructed from each of the two samples. What is the probability that at the same time, X E CI2 and X2 E CI? 2....
Suppose the heights of 18-year-old men are approximately normally distributed, with mean 69 inches and standard deviation 1 inch. If a random sample of thirty 18-year-old men is selected, what is the probability that the mean height x is between 68 and 70 inches? (Round your answer to four decimal places.)
of 18-year-old men are approximately normally distributed, with mean 67 inches and standard deviation 1 inches a) What is the probability that an 18- year-old man selected at r andom is between 66 and 68 inches tall? (Round your anewer to four (b) If a random sample of twenty-aight 18-year-old men is selected, what is the probability t decimal places.) hat the mean height i is between 66 and 6e inches? (Round your answer to four