6.875° C
the mean of a set of data is calculated using
mean = [tex]\frac{sum}{count}[/tex]
For the first 7 days the mean is 8 and the count = 7
8 = [tex]\frac{sum}{7}[/tex] ( cross- multiply )
sum = 8 × 7 = 56
Add on the temperature on the 8 th day to the sum and divide by 8 for mean
sum = 56 - 1 = 55
mean = [tex]\frac{55}{8}[/tex] = 6.875° C
