Standard deviation is: It is a measure of how spread out numbers are. It is the square root of the Variance, and the Variance is the average of the squared differences from the Mean.
For example: To find the standard deviation, you have to add up all the numbers in the data set, then divide by how many numbers there are, and that will get you your answer.
Example, Say your data set is: 9, 2, 5, 4, 12, 7, 8, 11, 9, 3, 7, 4, 12, 5, 4, 10, 9, 6, 9, 4.
The Mean is: 9 + 2 + 5 + 4 + 12 + 7 + 8 + 11 + 9 + 3 + 7 + 4 + 12 + 5 + 4 + 10+ 9 + 6 + 9 + 4. Over 20. That equals: 104 over 20 = 7.
So, the Standard Variance and Mean is: 7 for this problem.
Hope I helped!
- Debbie
Answer:
a) For the first part we have a sample of n =10 and we want to find the degrees of freedom, and we can use the following formula:
d.9
b) 
a.15
c) For this case we have the sample size n = 25 and the sample variance is 
, the standard error can founded with this formula:
Step-by-step explanation:
Part a
For the first part we have a sample of n =10 and we want to find the degrees of freedom, and we can use the following formula:
d.9
Part b
From a sample we know that n=41 and SS= 600, where SS represent the sum of quares given by:
And the sample variance for this case can be calculated from this formula:
a.15
Part c
For this case we have the sample size n = 25 and the sample variance is , the standard error can founded with this formula:
Answer:
Distance between two points= √(x2-x1)²+(y2-y1)²
D= 15units
Let "k" be the y-coordinate of A
A(-6,k)
B(3,2)
15= √(3--6)²+(2-k)²
Taking square of both sides to eliminate the square root.
15²=(9)²+(2-k)²
225=81+4-4k+k²
k²-4k - 140=0
Using Quadratic Formula to evaluate
k= 14 or k=-10
The Possible coordinates of A are
(-6,14) or (-6,-10)
