Answer: A. 0.4899 B. 14
Step-by-step explanation:
If X = random variable
then, the standard deviation of the sampling distribution of X =
A.
GIven:
The standard deviation of the sampling distribution of X =
B. Let n be the sample size,
Hence, the required sample size = 14
Work Shown:
A = area of the triangle
A = base*height/2
A = 9*7/2 = 63/2 = 31.5 ... see note1 below
B = area of rectangle
B = base*height
B = 9*3 = 27
C = area of parallelogram
C = base*height .... see note2 below
C = 9*6 = 54
If you're confused where I got the 6 from, check out the attached image below.
D = total area of the composite figure
D = A+B+C
D = 31.5 + 27 + 54
D = 112.5
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note1: The vertical component of the triangle is 9 units because this is part of the rectangle. The rectangle has opposite sides that are the same length. The parallelogram's vertical sides are 9 units long as shown by the single tickmark.
note2: a rectangle is essentially a special case of a parallelogram. In other words, a rectangle is a parallelogram with 4 right angles. So this is why the formula "area = base*height" shows up identical for both rectangles and parallelograms. Keep in mind that the height is always perpendicular to the base. You will not use the segments marked with double tickmarks.
