Question 6.45

10. On the NASA space shuttle, six primary O-rings were used to seal the sections of the two solid-fuel rocket motors and keep hot gases from escaping and catastrophically igniting the liquid hydrogen fuel tank. The number of O-ring erosion problems and the launch temperature (in degrees Fahrenheit) are given for 23 successful flights between April 12, 1981, and January 12, 1986:

Mission O-Ring Incidents °F Mission O-Ring Incidents °F
1 0 66 13 0 67
2 1 70 14 2 53
3 0 69 15 0 67
4 0 68 16 0 75
5 0 67 17 0 70
6 0 72 18 0 81
7 0 73 19 0 76
8 0 70 20 0 79
9 1 57 21 2 75
10 1 63 22 0 76
11 1 70 23 1 58
12 0 78
  1. Which is the explanatory variable?
  2. Make a scatterplot. Is the association between these variables positive or negative?
  3. Describe the form and strength of the relationship.
  4. The forecasted temperature the morning of the January 28, 1986, launch of the Challenger was between 26°F and 29°F. Should this have been a cause for concern or not? Why?
  5. Would a different conclusion be reached by someone whose scatterplot contained only the seven flights for which there was at least one problem? Explain.