The age of trees in a certain forest has a normal distribution with a mean of μ=192.7 years and standard deviation of σ=13 years. A sample of 36 trees is randomly selected and the average age of these trees, x¯, is recorded.
The age of trees in a certain forest has a normal distribution with a mean of...
7) In a normal distribution with μ=14 and σ=2, find the mean of the distribution of sample means for samples of size 25. 8) In a normal distribution with μ=12 and σ=0.75, find the standard deviation of the distribution of sample means for samples of size 64. (Round to the nearest ten-thousandth.) 11)Your company manufactures hot water heaters. The life spans of your product are known to be normally distributed with a mean of 13 years and a standard deviation...
a. Consider a normal distribution with mean 20 and standard deviation 4. What is the probability a value selected at random from this distribution is greater than 20? (Round your answer to two decimal places. b. Assume that x has a normal distribution with the specified mean and standard deviation. Find the indicated probability. (Round your answer to four decimal places.) μ = 14.3; σ = 3.5 P(10 ≤ x ≤ 26) = c. Assume that x has a normal...
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:...
Let X represent the full height of a certain species of tree. Assume that X has a normal probability distribution with μ=24.7 ft and σ=54 ft. You intend to measure a random sample of n=229 trees. What is the mean of the distribution of sample means? μ¯x= What is the standard deviation of the distribution of sample means (i.e., the standard error in estimating the mean)? (Report answer accurate to 2 decimal places.) σ¯x=
Let X represent the full height of a certain species of tree. Assume that X has a normal probability distribution with μ = 148.6 ft and σ = 67.9 ft. You intend to measure a random sample of n = 193 trees. What is the mean of the distribution of sample means? μ ¯ x = What is the standard deviation of the distribution of sample means (i.e., the standard error in estimating the mean)? (Report answer accurate to 2...
Let XX represent the full height of a certain species of tree. Assume that XX has a normal probability distribution with μ=182.9μ=182.9 ft and σ=7.1σ=7.1 ft. You intend to measure a random sample of n=87n=87 trees. What is the mean of the distribution of sample means? μ¯x=μx¯= What is the standard deviation of the distribution of sample means (i.e., the standard error in estimating the mean)? (Report answer accurate to 4 decimal places.) σ¯x= σx¯=
Assume that x has a normal distribution with the specified mean and standard deviation. Find the indicated probability. (Round your answer to four decimal places.) μ = 8; σ = 2 P(7 ≤ x ≤ 11) = Assume that x has a normal distribution with the specified mean and standard deviation. Find the indicated probability. (Round your answer to four decimal places.) μ = 6.0; σ = 1.4 P(7 ≤ x ≤ 9) = Assume that x has a normal...
A certain population of children has height thus have a Normal Distribution with a mean of 40.8 inches and standard deviation of 2.4 inches. a) if 36 perosns are randomly selected from this population, find the probability that thieir mean height is at most 39 inches. Draw a good diagram to support your answer and show the z-score.
Consider a normal distribution with mean 25 and standard deviation 5. What is the probability a value selected at random from this distribution is greater than 25? (Round your answer to two decimal places.) Assume that x has a normal distribution with the specified mean and standard deviation. Find the indicated probability. (Round your answer to four decimal places.) μ = 14.9; σ = 3.5 P(10 ≤ x ≤ 26) = Need Help? Read It Assume that x has a...
The time needed for college students to complete a certain paper-and-pencil maze follows a normal distribution with a mean of µ = 30 seconds and a standard deviation of σ = 3 seconds. Nine randomly selected college students complete the maze. The sampling distribution of the sample mean X it takes the sampled students to complete the maze is A. normal with mean 30 and standard deviation 3. B. normal with mean 30 and standard deviation 1. C. negatively skewed...