1) Mean
The mean is given by the sum of the data divided by the number of data (4, in this case):

2) Standard deviation
The standard deviation is given by:

where

is the mean, that we already found at point 1), and N=4. Substituting data, we have:

#1
Clear shown in graph
#2
No
At. no where graph passes through origin so y intercept is not 0 at anywhere
#3
Domain is x values
#4
Range is y values set
Its the last one, the shapes but be polygons.
Answer: 92 dollars because 15% divided into 80 is 12 and add 80 to 12 and its 92