The standard deviation and the mean of 16 values are 15.6 and 20.5. What is the coefficient of variation ?

CV = coefficient of variation = 0.761

Step-by-step explanation:

The coefficient of variation is defined as the standard deviation divided by the mean of a population, which in this case,

standard deviation = 15.6

mean = 20.5

CV = coefficient of variation = 15.6/20.5 = 0.761

Note that if the 16 values form a sample (i.e. not the entire population), the above result is an estimate of the CV.

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this