9) how do you know a chemical change has occurred? a. new bonds have formed or bonds have broken. b. the matter has had a change in state. c. the temperature has changed. d. all of the above e. only a and c are indicators of a chemical change. ! 15 pts 10) if a chemical bond is formed or destroyed, what changes? a. energy is absorbed or released. b. protons are absorbed. c. neutrons will vary. d. energy is destroyed. e. protons are released.

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.