=+. A random sample of 24 phone conversation was recorded by a local university switch board and the time spent in conversation (in minutes) was noted below:

38.12 2.7 32.82 47.51 36.52 34.2 64 52 26.6 31 5 12.4 32 4 1 17 18 33 12 6 8 42 15 16 The average was 24.45 minutes and the standard deviation was 17.23 minutes