In a sample of n= 11 lichen specimens, the researchers found the mean and standard deviation...
A company wants to test a randomly selected sample of n water specimens and estimate the mean daily rate of pollution produced by a mining operation. If the company wants a 95% confidence interval estimate with a margin of error of 1.7 milligrams per liter (mg/L), how many water specimens are required in the sample? Assume prior knowledge indicates that pollution readings in water samples taken during a day are approximately normally distributed with a standard deviation equal to 7...
A simple random sample of size n is drawn. The sample mean,x overbarx, is found to be 17.8 and the sample standard deviation, s, is found to be 4.4 (a) Construct a 95% confidence interval about μ if the sample size, n, is 35 Lower bound: ____ Upper bound: ______ (Use ascending order. Round to two decimal places as needed.) (b) Construct a 95% confidence interval about μ if the sample size, n, is 51 Lower bound: ____ Upper bound:...
The mean and standard deviation of a random sample of n measurements are equal to 33.3 and 3.3, respectively. a. Find a 95 % confidence interval for μ if n=144. b. Find a 95 % confidence interval for μ if n= 576 c. Find the widths of the confidence intervals found in parts a and b. What is the effect on the width of a confidence interval of quadrupling the sample size while holding the confidence coefficient fixed? a.The 95%...
The mean and standard deviation of a random sample of n measurements are equal to 33.5 and 3.1, respectively. a. Find a 95% confidence interval for μ if n=49. b. Find a 95% confidence interval for μ if n=196. c. Find the widths of the confidence intervals found in parts a and b. What is the effect on the width of a confidence interval of quadrupling the sample size while holding the confidence coefficient fixed? a. The 95% confidence interval...
11. A simple random sample of size n is drawn. The sample mean, X, is found to be 17.9, and the sample standard deviation, s, is found to be 4.5. Click the icon to view the table of areas under the t-distribution. (a) Construct a 95% confidence interval about if the sample size, n, is 34. Lower bound: : Upper bound: (Use ascending order. Round to two decimal places as needed.) (b) Construct a 95% confidence interval about if the...
Consider a population having a standard deviation equal to 9.96. We wish to estimate the mean of this population. (a) How large a random sample is needed to construct a 95% confidence interval for the mean of this population with a margin of error equal to 1? (Round your answer to the next whole number.) The random sample is units. (b) Suppose that we now take a random sample of the size we have determined in part a. If we...
For the provided sample mean, sample size, and population standard deviation, complete parts (a) through (c) below. Assume that x is normally distributed x= 27, n=9, 0 = 6 a. Find a 95% confidence interval for the population mean The 95% confidence interval is from to (Round to two decimal places as needed.) b. Identify and interpret the margin of error. The margin of error is (Round to two decimal places as needed.) Interpret the margin of error. Choose the...
For the provided sample mean, sample size, and population standard deviation, complete parts (a) through (c) below. x= 23, n= 36, 3 = 3 a. Find a 95% confidence interval for the population mean. The 95% confidence interval is from to (Round to two decimal places as needed.) b. Identify and interpret the margin of error. The margin of error is (Round to two decimal places as needed.) Interpret the margin of error. Choose the correct answer below. O A....
6. A sample of size n- 200 has a known population standard deviation of 15.0. The population appears to be skewed. Determine whether a margin of error should be calculated using a critical value of za, a critical value of ta/2, or neither. Oa critical value of ta2 O a critical value of za O neither 7. The mean of a sample size n 35 is 1860. The standard deviation of the sample is 102 and the population is normally...
The mean and standard deviation of a random sample of n measurements are equal to 33.5 and 3.3, respectively. a. Find a 95% confidence interval for if n-49 b. Find a 95% confidence interval for if n-196. c. Find the widths of the confidence intervals found in parts a and b. What is the effect on the width of a confidence interval of quadrupling the sample size while holding the confidence coefficient fixed? a. The 95% confidence interval for μ...