At Burnt Mesa Pueblo, archaeological studies have used the method of tree-ring dating in an effort to determine when prehistoric people lived in the pueblo, Wood from several excavations gave a mean of year) 1233 with a standard deviation of 39 years. The distribution of dates was more or less mound-shaped and symmetrical about the mean. Use the empirical rule to estimate the following. (a) a range of years centered about the mean in which about 68% of the data (tree-ring dates) will be found between 1188 X and 1278 X A.D. (b) a range of years centered about the mean in which about 95% of the data (tree-ring dates will be found between 1143 X and 1323 X A.D. (c) a range of years centered about the mean in which almost all the data (tree-ring dates) will be found between 1098 X and 1368 X A.D