The standard deviation of a variable is 15 . If a sample of 70 individuals is selected, (a) Find the standard error of the mean. Round the answer to three decimal places.   Standard error of the mean  =   (b) Find the sample size needed to cut the standard error of the mean in half. Round intermediate calculations to three decimal places and round your final answer up to the nearest whole number.   Sample size  =

The frequency distribution was obtained using a class width of 0.5 for data on cigarette tax rates. Use the frequency distribution to approximate the population mean and population standard deviation. Compare these results to the actual mean μ = $1.638 and standard deviation o = $1.052. Click the icon to view the frequency distribution for the tax rates. The population mean is $ (Round to three decimal places as needed.) book Get more help. C *** Frequency distribution of cigarette tax rates G Search or type URL Tax Rate 0.00-0.49 0.50-0.99 1.00-1.49 1.50-1.99 2.00-2.49 2.50-2.99 3.00-3.49 3.50-3.99 4.00-4.49 Print Frequency O 7 12 6 6 6 6 3 3 1 Done - X Clear all Check answer

← The numbers of regular season wins for 10 football teams in a given season are given below. Determine the range, mean, variance, and standard deviation of the population data set. 2, 10, 15, 4, 12, 9, 13, 10, 5, 7 The range is 13. (Simplify your answer.) The population mean is 8.7. (Simplify your answer. Round to the nearest tenth as needed.) The population variance is 15.6. (Simplify your answer. Round to the nearest tenth as needed.) The population standard deviation is (Simplify your answer. Round to the nearest tenth as needed.)

The coefficient of variation CV describes the standard deviation as a percent of the mean. Because it has no units, you can use the coefficient of variation to compare data with different units. Find the coefficient of variation for each sample data set. What can you conclude? Standard deviation CV = • 100% Mean E Click the icon to view the data sets. Data Table C/heights = 5.0 % (Round to the nearest tenth as needed.) Heights Weights CVweights =% (Round to the nearest tenth as needed.) 68 181 77 169 72 167 72 207 71 177 70 175 78 185 69 186 67 221 70 216 67 209 73 206