Final answer:
The integer representing Tiana's decrease in running time by 2 minutes is -2, indicating that the time taken to complete her run is 2 minutes less than the previous week.
Step-by-step explanation:
The student's question is about representing the change in Tiana's running time as an integer. Since Tiana's time spent running decreased by 2 minutes, the integer representing this change would be -2.
The change is negative because the time taken to complete the run has decreased from the previous week, indicating an improvement in speed. Therefore, if Tiana were to record this change, she would note it as -2 minutes. Always remember, when it comes to changes in time, speed, or any other quantity, if there is a decrease, the change is represented by a negative number, and if there is an increase, it is represented by a positive number.