A rectangular room 14 feet by 12 feet has a semicircular sitting area attached with a diameter of 12 feet. What is the total are
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Answer:
(a) The distribution of the sample mean () is <em>N</em> (68, 4.74²).
(b) The value of is 0.7642.
(c) The value of is 0.3670.
Step-by-step explanation:
A random sample of size <em>n</em> = 10 is selected from a population.
Let the population be made up of the random variable <em>X</em>.
The mean and standard deviation of <em>X</em> are:
(a)
According to the Central Limit Theorem if we have a population with mean <em>μ</em> and standard deviation <em>σ</em> and we take appropriately huge random samples (<em>n</em> ≥ 30) from the population with replacement, then the distribution of the sample mean will be approximately normally distributed.
Since the sample selected is not large, i.e. <em>n</em> = 10 < 30, for the distribution of the sample mean will be approximately normally distributed, the population from which the sample is selected must be normally distributed.
Then, the mean of the distribution of the sample mean is given by,
And the standard deviation of the distribution of the sample mean is given by,
Thus, the distribution of the sample mean () is <em>N</em> (68, 4.74²).
(b)
Compute the value of as follows:
*Use a <em>z</em>-table for the probability.
Thus, the value of is 0.7642.
(c)
Compute the value of as follows:
Apply continuity correction as follows:
Thus, the value of is 0.3670.
<h3>Answer: As a fraction, HC is 21/4 units long</h3><h3>In decimal form, HC is 5.25 units long.</h3>
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Work Shown:
Let x = HC and y = BH
AH = 12-x since AH = 12-HC and x = HC
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See the attached drawing below. The altitude BH forms three similar triangles which makes the proportion below possible
HC/BH = BH/AH
x/y = y/(12-x) ... substitution
x(12-x) = y^2 ... cross multiply
y^2 = -x^2+12x
note how I isolated y^2 instead of y. We will use this equation later.
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Focus on triangle AHB. Use the pythagorean theorem
(BH)^2 + (AH)^2 = (AB)^2
(y)^2 + (12-x)^2 = (9)^2
y^2 + 144-24x+x^2 = 81
-x^2+12x + 144-24x+x^2 = 81 ... replace y^2 with -x^2+12x
-x^2+12x + 144-24x+x^2-81 = 0
-12x + 63 = 0
-12x = -63
x = -63/(-12)
x = 5.25 <<-- answer in decimal form
x = 5 + 0.25
x = 5 + 1/4
x = 20/4 + 1/4
x = 21/4 <<-- answer as a fraction