8.18 If the standard deviation of the mean for the sampling distribution of random samples of size 36 from a large or infinite population is 2, how large must the sample size become if the standard deviation is to be reduced to 1.2?
Q: If the standard deviation of the mean for the sampling distribution of random samples of size 36…
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Q: 20. A very large population has a mean of 55 and a standard deviation of 8. One day a sample of 40…
A: Solution: 20. From the given information, µ = 55 and σ = 8.
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A: Givensample size(n)=36population standard deviation(σ)=6
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Q: For a population with a mean of μ = 55 and a standard deviation of σ = 69, what is the standard…
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- Suppose a random sample of 4949 measurements is selected from a population with mean 6060 and standard deviation 1010. Step 2 of 2: Find the standard deviation of the sampling distribution of sample means using the given information. Round to two decimal place, if necessary.A population is known to be normally distributed with standard deviation known to be 6.3. In order to test the hypothesis that the true value of the mean is 19 researchers collect a sample of size 36 and calculate the sample mean to be 16. State the distribution of the sample mean and then test this hypothesis using the appropriate test.A random sample of n=16 scores is obtained from a population with a standard deviation of 16. If the sample mean is greater than 8 points greater than the population mean, what is the z-score for the sample mean?
- 4. A distribution of scores has = 70. The z-score for X = 65 is computed and a value of z = +1.00. Regardless of the value of the standard deviation, why must this z-score be incorrect?4. A normal population has the mean of 20 and the variance of 100. A random sample of size n = 69 is selected. (a) Find the standard deviation of the sample mean. (b) How large must the sample be if you want to halve the standard deviation of the sample mean?If the random variable of X is normally distributed with a mean of 50 and a standard deviation of 10, approximately what % of all possible observed values of X will lie between 30 and 70.
- For a population with a mean of μ = 55 and a standard deviation of σ = 23, what is the standard error of the distribution of sample means for a sample size of n=6? leave the answer to the nearest hundredths place.4. A very large population has a mean of 180 and a standard deviation of 24. One day a sample of 64 observations is taken. On another day a sample of 100 observations is taken. Which of the following is true? The standard error of the mean will be smaller with 64 observations. It is impossible to determine any of the above given the available information. The standard error of the mean will be larger with 64 observations. The standard error of the mean will be the same with either 64 or 100 observations.Consider the distribution of the average number of hours that college students spend sleeping each weeknight. This distribution is very skewed to the right, with a mean of 5 and a standard deviation of 1. A researcher plans to take a simple random sample of 18 college students. If we were to imagine that we could take all possible random samples of size 18 from the population of college students, the sampling distribution of the average number of hours spent sleeping will have a shape that is ☐ Exactly normal. Just like the population (i.e., very skewed to the right). Less skewed than the population.
- A population is known to be normally distributed with standard deviation known to be 8.5. In order to test the hypothesis that the true value of the mean is 17 researchers collect a sample of size 33 and calculate the sample mean to be 14. State the distribution of the sample mean and then test this hypothesis using the appropriate test.13.36 (EX) Pregnancy lengths 1/2: The length of human pregnancies from conception to birth varies according to a distribution that is approximately Normal with mean 266 days and standard deviation 16 days. A study enrolls a random sample of 16 pregnant women. The mean of the sampling distribution of is 266 ¡X is The standard deviation of the sampling distribution of 4 (No decimal) (No decimal)Suppose we are about to sample 200 values from a normally distributed population that has a mean of 120 and a standard deviation of 70. What is the 10th percentile of the sampling distribution of the sample mean in this scenario? (Give your numeric response to at least 3 decimal places. Give only your numeric response, and no extra characters or symbols.)
