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:

Explanation : % is the symbol for percentage. It means out of 100. 75% means 75 out of 100 which is represented as 75/100.
Answer:
AB= 8/Cosine 60 degrees
Step-by-step explanation:
Cosine=Adjacent/Hypotenuse
Cosine=8/AB
AB=8/Cosine 60 degrees
It would be approximately 23 cents per fluid ounce.
Answer:
D. 9990 possible combinations
Step-by-step explanation:
The first digit has 10 choices (can be all of them), the second digit also has 10 choices. The third and fourth digits also have 10 choices.
Multiply them together you get 10*10*10*10 = 10000 possible combinations.
But since all 4 characters cannot be the same, we subtract 10 from 10000 (there are 10 combinations which the 4 characters are the same: 1111, 2222, 3333, 4444, 5555, 6666, 7777, 8888, 9999, and 0000) and we get 9990.