The following is data you have collected over a 20-day period. 1 199 202 199 196 199 196 2 195 200 200 203 196 205 3 201 194 197 204 207 197 4. 205 204 201 195 194 200 5 205 203 198 197 199 197 6 207 195 206 205 188 198 7 191 202 199 202 200 200 8 199 202 194 207 205 204 9 204 206 192 197 203 197 10 196 198 214 197 194 206 11 197 200 200 200 207 199 12 193 189 198 202 195 202 13 193 202 207 209 208 203 14 196 205 198 204 192 194 15 197 198 197 206 201 200 16 192 194 200 192 196 199 17 198 201 191 197 200 201 18 198 205 205 201 202 198 19 201 196 197 193 211 198 20 199 200 199 198 200 195 Mean SD CV QUESTIONS 1. How do you determine the mean of each column of data? 2. Calculate the mean for each group of data and write your answers in the space provided at the bottom. 3. What does the mean tell you about the method performance? 4. How do you determine the standard deviation of each column of data? 5. Calculate the standard deviation for each column of data and write your answers in the space provided at the bottom. 6. What does the standard deviation tell you about the method performance? 7. What is a CV? 8. Why is a CV useful? 9. Calculate the CV for each column of data and write your answers in the space provided at the bottom. 10. How do you calculate the control limits using the mean and standard deviation? 11. For each column of data, plot the values on individual Levy-Jennings charts provided. Be sure to use the mean and SD for that set of values. 12. Based on the information you have obtained, which set of data is the most accurate? Why? 68% 95% 99% -3SD -2SD -1SD Mean +1SD +2SD +3SD 1 2 3 4 5 6 7 8 9 10 11 12