Answer:
3. Standard deviation is the square root of the variance.
4. Standard deviation is useful because it has the same units as the underlying data.
Step-by-step explanation:
3. In statistics, the dispersion in a given data with respect to its mean distribution can be determined or measured by standard deviation and variance. The standard deviation of a distribution can also be determined as the square root of variance.
4. Standard deviation is measured in the same units as that of the original data. Thus it has the same units as the underlying data.
Answer:
The length of the midsegment is 9 ⇒ (B)
Step-by-step explanation:
In a triangle,
- The midsegment is the segment which joining the midpoints of two opposite sides of it
- The length of the midsegment is half the length of the third side in the triangle which opposite to it
<em>Let us use this rule to solve our question</em>
In Δ AC
∵ DE is the midsegment of it
∵ DE is opposite to the side AC
∴ The length of DE = 1/2 the length of AC
∵ The length of AC = 18
∴ The length of DE = 1/2 × 18
∴ The length of DE = 9
∴ The length of the midsegment is 9
The correct answer is B
Answer:

Step-by-step explanation:
Since we cannot factor the expression, we must use quadratic formula: 
Plug in <em>a</em> for 2, <em>b</em> for 3, and <em>c</em> for -7 and you should find your roots.
I believe you do it like this:
1/2 Q+5/2
divide 1/2 into each term
to divide multiply by the reciprocal
1/2 x2/1= 1
5/2 x 2/1=5
1/2(Q+5)
Remember
you can do anyting to an equaiton as long as you do it to both sidess
distributive property
a(b+c)=ab+ac
commutativ property
a+b=b+a
distribute
3(4x-2)=12x-6
12x-6=9+2x+5
add 6 both sides
12x+6-6=9+6+5+2x
12x+0=20+2x
minus 2x
10x=20
divide 10
x=2