points.

b. Find a 95% confidence interval for the true mean external tension level of all managers who engage in coopetition.

c. Explain how the confidence interval of part b can be used to infer whether or not the true mean differs from 10.5.

d. The test, part

a, yields a “statistically significant” result. Use the confidence interval, part

b, and the fact that external tension is measured on a 20-point scale to comment on whether the result is “practically significant.”