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.
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The expectation is the average value or mean of a random variable. As such it is for discrete random variables the weighted average of the values the random variable takes.
A sample is selected from a population with a mean of µ=80 and a standard deviation...
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 population forms a normal distribution with a mean of µ = 120 and a standard deviation of σ = 14. If two scores were selected from this population, how much distance would you expect, on average, between the second score and the population mean? A sample of n = 20 scores from this population has a mean of M = 90, do you think this sample is relative typical or extreme to the population? Explain. With a large standard...
A random sample of size 36 is taken from a population with mean µ = 18 and standard deviation σ = 5. What are the expected value and the standard deviation for the sampling distribution of the sample mean? Group of answer choices a. 1.425 and 2.66, respectively b. 18 and 5, respectively c. 1.425 and 0.83, respectively d. 18 and 0.83, respectively
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.
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...
A random sample is selected from a population with mean μ = 102 and standard deviation σ = 10. Determine the mean and standard deviation of the xbar sampling distribution for each of the following sample sizes. (Round the answers to three decimal places.) (a) n = 15 μ = σ = (b) n = 35 μ = σ = (c) n = 55 μ = σ = (d) n = 110 μ = σ = (e) n = 440...
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 sample of 44 observations is selected from one population with a population standard deviation of 3.1. The sample mean is 101.0. A sample of 56 observations is selected from a second population with a population standard deviation of 5.0. The sample mean is 99.5. Conduct the following test of hypothesis using the 0.10 significance level. H0 : μ1 = μ2 H1 : μ1 ≠ μ2 Is this a one-tailed or a two-tailed test? One-tailed test Two-tailed test State the...
A random sample of size 36 is to be selected from a population that has a mean μ = 50 and a standard deviation σ of 10. * a. This sample of 36 has a mean value of , which belongs to a sampling distribution. Find the shape of this sampling distribution. * b. Find the mean of this sampling distribution. * c. Find the standard error of this sampling distribution. * d. What is the...
A population has a mean of 200 and a standard deviation of 80. Suppose a sample of size 100 is selected and x̅ is used to estimate μ. a. What is the probability that the sample mean will be within +/- 9 of the population mean (to 4 decimals)? b. What is the probability that the sample mean will be within +/- 14 of the population mean (to 4 decimals)?