The 5 a.m. temperatures for seven consecutive days were $-7^{\circ}$, $-4^{\circ}$, $-4^{\circ}$, $-5^{\circ}$, $1^{\circ}$, $3^{\circ}$ and $2^{\circ}$ Celsius. What is the mean 5 a.m. temperature for the week in degrees Celsius?
I need to find the mean temperature, which is the average of all the temperatures. To do that, I need to add up all the temperatures and divide by the number of days, which is 7. Adding up the temperatures, I get $-7 + (-4) + (-4) + (-5) + 1 + 3 + 2 = -14$. Dividing by 7, I get $-14 \div 7 = -2$. So the mean temperature is $-2^{\circ}$ Celsius. 