Question

The following data are the joint temperatures of the O-rings (F) for each test firing or actual launch of the space shuttle rocket motor (from Presidential Commission on the Space Shuttle Challenger Accident, Vol. 1, pp. 129-131): 82 47 61 40 83 67 45 66 70 69 80 58 68 60 67 72 73 70 57 63 70 78 52 67 53 67 75 61 70 81 76 79 75 76 58 31 Round your answers to 2 decimal places (e.g. 98.76). (a) Using the entire data, calculate the sample mean and sample standard deviation. Sample mean = Sample standard deviation = (b) Remove the smallest observation (31°F) and calculate the sample mean and sample standard deviation of the remaining data. Sample mean = Sample standard deviation = (c) With the smallest observation removed: the sample mean and the sample standard deviation

Answer 1

The statistical software output with and without smallest observation is:

Summary statistics: Column Mean Std. dev. With 31 C 65.75 12.161708 Summary statistics: Column Mean Std. dev. Without 31 C 66.742857 10.757604

Hence,

a) Mean = 65.75

SD = 12.16

b) Mean = 66.74

SD = 10.76

c) Increases; Decreases