<prompt> In a bell-shaped standard normal curve, mean -2 standard detions covers:60659599  <response>: If the distribution of observations is bell-shaped, then even more can be said about the percentage of observations that lay between the mean and - 2 standard detions. For a bell-shaped distribution, approximately: 67 of the observations lie between the mean - 1 standard detion 95 of the observations lie between the mean - 2 standard detions 99.7 of the observations lie between the mean - 3 standard detions Ref: Dawson B., Trapp R.G. 2004. Chapter 3. Summarizing Data Presenting Data in Tables Graphs. In B. Dawson, R.G. Trapp Eds, Basic Clinical Biostatistics, 4e. 