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:

Find the slop equation.
Slope: -3
Y-intetrcept: -3

Now write it as an inuquality.
It's shaded to the left and the line is not fully filled in. Which means that whatever "y" is, it's Less than the and equal to the slope.

Hope this helps :)
Answer:
The loose sweets at ?0.89 for 100 g.
Step-by-step explanation:
First, calculate the price per gram. You do this by dividing the price by the grams.
?1.49 / 120 g = 1.49 / 120 = 0.0124 (4 dp)
Because the answer was very long, I have rounded it to 4 decimal places (4 dp).
?0.89 / 100 g = 0.89 / 100 = 0.0089
Next, you must calculate both pre-packed and loose sweets to the same weight. I am calculating them both to 100 g.
0.0124 x 100 = 1.24
0.0089 x 100 = 0.89
Finally, the cheapest product for 100 g will be the better value. In this case, it is the loose sweets.