The random variable X has mean 12 and standard deviation 3. The random variable W is defined as W=7+2X . What are the mean and s
2 answers:
Answer:
The mean and standard devaition of W are 6 and 31 respectively.
Step-by-step explanation:
Given that:
W = 7 + 2X
Variance (W) = Variance(7 + 2X)
For a term constant term, the variance is zero.
So;
W = 4 × Var(X)
W = 4 × (SD (X))²
W = 4 × (3)²
W = 4 × 9
W = 36
Thus, Variance (W) = 36
The standard deviation of W =
W =
W = 6
Also;
E(W) = E(7 +2 X)
E(W) = 7 + 2 × E(X)
where;
mean X = 12
E(W) = 7 + 2(12)
E(W) = 31
Thus, the mean and standard devaition of W are 6 and 31 respectively.
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Answer:
a) Area of the base of the pyramid =
b) Area of one lateral face =
c) Lateral Surface Area =
d) Total Surface Area =
Step-by-step explanation:
We are given the following dimensions of the triangular pyramid:
Side of triangular base = 6mm
Height of triangular base = 5.2mm
Base of lateral face (triangular) = 6mm
Height of lateral face (triangular) = 8mm
a) To find Area of base of pyramid:
We know that it is a triangular pyramid and the base is a equilateral triangle.
b) To find area of one lateral surface:
Base = 6mm
Height = 8mm
Using equation (1) to find the area:
c) To find the lateral surface area:
We know that there are 3 lateral surfaces with equal height and equal base.
Hence, their areas will also be same. So,
d) To find total surface area:
Total Surface area of the given triangular pyramid will be equal to <em>Lateral Surface Area + Area of base</em>
Hence,
a) Area of the base of the pyramid =
b) Area of one lateral face =
c) Lateral Surface Area =
d) Total Surface Area =