To find percent error, you subtract the actual number from your estimate, take the absolute value, and divide by the actual number.
l 96 - 118 l
l -22 l
l 22 l
l 22 l / 118
0.19% (this was rounded)
Hope this helps!
The error bars are used to indicate the variability of the data presented in a graph.
There are several quantities that can be used to generate error bars in the graph. These are:
standard deviation
standard error
confidence interval
Usually, one standard deviation above and below the mean is used although it is advised to indicate which variability data is used to generate the error bars in the graph since the 3 quantity given are not equal.
Problem 5
x = number of songs downloaded
MyTunes charges $2.50 per song, so you pay 2.50*x dollars if you download x songs. If M is the cost of using MyTunes, then M = 2.50*x.
Let G be the cost of using Great Songs. The equation here is G = 1.50*x+50. We have 1.50*x representing the cost of downloading x songs (at 1.50 dollars a piece) plus the membership fee of $50. So the total cost here is 1.50x+50 dollars.
We want to find out when Great Songs is a better deal, so we want to determine what x values make G smaller than M
(Great Songs Cost) < (MyTunes Cost)
G < M
1.50x+50 < M ................................... replace G with 1.50x+50
1.50x+50 < 2.50x ............................. replace M with 2.50x
1.50x+50-1.50x < 2.50x-1.50x ....... subtract 1.50x from both sides
50 < 1.00x
50 < x
x > 50
If you download more than 50 songs, then Great Songs will be the better deal since it will be the cheaper plan.
