Oscar measures the temperature of the solution at the beginning of an experiment to be 34 degrees F. He monitors the temperature of the solution every minute for 10 minutes. He records the change in temperature from the previous reading. His data show a decrease of 3 degrees F four times, a decrease of 5 degrees F three times, no temperature two times, and an increase of 8 degrees. Write an expression to represent the average change in the change in temperature each minute.