8. A dataset has a mean of µ = 1.2 and a standard deviation of σ = 0.9. How many standard deviations away is 5? How many standard deviations away is 1.5? -2? 0? 5?
8)
The mean and standard deviation are and respectively.
Number of standard deviations that 5 is away from the mean =
Number of standard deviations that 1.5 is away from the mean =
Number of standard deviations that -2 is away from the mean =
Number of standard deviations that 0 is away from the mean =
Suppose that the monthly return of stock A is approximately normally distributed with mean µ and standard deviation σ, where µ and σ are two unknown parameters. We want to learn more about the population mean µ, so we collect the monthly returns of stock A in nine randomly selected months. The returns are given (in percentage) as follows: 0.3, 1.3, 1.5, −0.6, −0.2, 0.8, 0.8, 0.9, −1.2 Answer the following questions about the confidence intervals for µ. (a) Construct...
Given a population with a mean of µ = 270 and a standard deviation σ = 29, assume the central limit theorem applies when the sample size is n ≥ 25. A random sample of size n = 220 is obtained. Calculate σx¯
A normally distributed population has a mean of µ = 70 and a standard deviation of σ = 12. A sample (n = 36) is selected from a population and a treatment is administered to the sample. After treatment, the sample mean is found to be M = 65. Does this sample provide evidence of a statistically significant treatment effect with an alpha of 0.05 (non-directional hypothesis)? [G&W Chp 8] Yes, our z-score reaches the critical region. No, our z-score fails to...
The national average for the SAT is 1028 (µ and the standard deviation is 100 (σ = 100). Find the Percentile for a score of 1065 for: A single student (n=1) For a mean of 50 students (n=50) For a mean of 500 students (n=500)
A sample is selected from a population with a mean of µ=80 and a standard deviation of σ=20. What is the expected value of the mean? Just put number. You do not have to put symbol in front of answer.
A sample is selected from a population with a mean of µ=80 and a standard deviation of σ=20. What is the expected value of the mean? Just put number. You do not have to put symbol in front of answer.
Suppose that the weight of Florida navel oranges is normally distributed with mean µ = 8 ounces, and standard deviation σ = 1.5 ounces. (a) (1 point) State the model in notation form. (b) (2 points) What proportion of oranges weigh more than 11.5 ounces? (c) (2 points) What proportion of oranges weigh less than 8.7 ounces? (d) (2 points) What proportion of oranges weigh between 6.2 and 7 ounces? Page 3 (e) (5 points) What are the median, mode,...
1. X has a normal distribution with the given mean and standard deviation. Find the indicated probability. (Round your answer to four decimal places.) μ = 41, σ = 20, find P(35 ≤ X ≤ 42) 2. Find the probability that a normal variable takes on values within 0.9 standard deviations of its mean. (Round your decimal to four decimal places.) 3. Suppose X is a normal random variable with mean μ = 100 and standard deviation σ = 10....
The mean is μ = 15.2 and the standard deviation is σ = 0.9. Find the probability that X is between 14.3 and 16.1.
3. On one I.Q. test, the mean score (µ) is 100 and the population standard deviation (σ) is 15. A sample of 50 scores is selected from a very large population. Find the probability that the mean of the sample group is more than 103.