The answer is
7.9306Using the formula in the attached:
Where: xi = sample value; μ = sample mean; n = sample size
1.) Calculate the mean first:
μ = 12.0 + 18.3 + 29.6 + 14.3 + 27.8 / 5
= 102 / 5
μ = 20.4
2.) Using the mean, calculate (xi - μ)² for each value:
(12.0 - 20.4)² = 70.56
(18.3 - 20.4)² = 4.41
(29.6 - 20.4)² = 84.64
(14.3 - 20.4)² = 37.21
(27.8 - 20.4)² = 54.76
3.) Sum the squared differences and divide by n - 1.
μ = 70.56 + 4.41 + 84.64 + 37.21 + 54.76
= 251.58 / 5-1
μ =
62.895 (this is now called sample variance)
4.) Get the square root of the sample variance:
√62.895 =
7.9306
I'm assuming this is a Pythagorean theorem problem. If so the answer would be √125
Solution: We are given:
Predicted Sales by Sameera 
Actual Sales by Sameera 
Now to find the Percent error, we have to use the below formula:



Therefore, the percent error is
<span>the answer will have to be the second choice cause it seems more correct</span>
Question 4
The magnitude;
Using Pythagoras theorem,
(-200)² + (-530)² = 320900
Length = √320900
= 566.5 mi
To get the angle
Tan θ = opposite/adjacent
= 200/530
= 0.3774
θ = tan^-1 (0.3774)
= 20.67
≈ 21°
The direction from the Cartesian plane is south of west.
Therefore, the magnitude and the direction will be;
About 566.5 mi, 21° south of west
Question 5.
To get the resultant of two vectors we just add the two vectors given.
This involves adding the corresponding values.
Thus, for <-6,5> and <6,-5>
Resultant vector = <(-6+6),(5+-5>
= <0,0>