Standard deviation is calculated by
1. calculate mean, m
2. calculate deviation of EACH entry of data set from the mean, i.e.
d=(x-m)
3. calculate mean of square of deviations (d^2)/n to get variance,v
4. take square-root of variance to get standard deviation.

For example,
To find the standard deviation of data set {3,7,8}
1. mean=(3+7+8)/3=6
2. deviations, di={3-6,7-6,8-6}={-3,1,2}
3. squares of deviations, di^2={9,1,4}
4. mean of squares of deviations=(9+1+4)/3=14/3
Standard deviation=sqrt(14/3)=2.16

For the given data set, if you follow the above steps, you would get
sum=400
mean=400/9
variance (mean square of deviations)=8246/81
standard deviation=sqrt(8246/81)=sqrt(8246)/9

3 0

3 years ago

Burka [1]

Answer:

Step-by-step explanation:

$F \alpha \frac{1}{d^{2} }$

$F = \frac{K}{d^{2} }$

When F = 18; d = 2

$18 = \frac{K}{2^{2} }$

$18 = \frac{K}{4}$

Cross multiply;

18 x 4 = K

72 = K

There the equation connecting F and $d^{2}$ is

$F = \frac{72}{d}$

Now, Find F when d = 6

All you do is to substitute d = 6 in to $F = \frac{72}{d}$

$F = \frac{72}{6}$

Therefore;

F = 12

Please mark me brainiest if correct.

6 0

3 years ago

Lori has 60% of the book to read. If she has read 120 pages how many pages does she still have to read

maks197457 [2]

Ok, so 120 pages plus the 60% of the book she has left to read will give the total number of pages.

That means that 120 pages is 40% of the book.

Make a proportion

120/40% = x/60%

72 = .4 x

x = 180 pages

5 0

4 years ago

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