Metric: kilometers
Imperial: Miles
Answer:
A
Step-by-step explanation:
I just took the test and i got it correct! :)
In addition to mean and sample size you will need the individual scores.
The formula for standard deviation is:
S^2 = E(X-M)^2/N-1
Here's an example:
Data set: 4,4,3,1
Mean: 3
Sample size: 4
First, put the individual scores one after the other and subtract the mean from it.
4 - 3 = 1
4 - 3 = 1
3 - 3 = 0
1 - 3 = -2
Second, square the answers you got from step 1.
1^2 = 1
1^2 = 1
0^2 = 0
-2^2 = 4
Third, plug the values from step 2 into the formula.
S^2 = (1+1+0+4)/(4-1) = 6/3 = 2
Standard deviation = 2
By Pythagoras AB^2 = 12^2 - 6^2 = 108
AB = sqrt 108 = 10.39 to nearest hundredth
The perpendicular from M to DC will be parallel and equal to AB so it = 10.39.
Also AB^2 = CB * DB
108 = 6 * DB
DB = 108/6 = 18
so DC = 18-6 = 12
MD^2 = (1/2*12)^2 + 108 = 144
so MD = 12
