Answer:
-10°F
Explanation:
We want to find the average low temperature for the five days. To find an average, add up every value, then divide by the number of values. 
The data given is: 
 -8°F, -13°F,  -4°F, -9°F, -16°F
1. Add the values 
-8 + -13 + -4 + -9 + -16
-50 
2. Divide by the number of values
Count how many numbers there are. The data was for 5 days, so there are 5 values. 
-50/5 
-10 
The average low temperature for the 5 days was -10 degrees Fahrenheit.