A finance magazine did a survey and found that the average American family spends $1,600 on a summer vacation. If the distributi
on is normal with standard deviation $411, find the amount a family would have spent to be the 80th percentile. PreviousNext
1 answer:
Answer:
<h2> $1945</h2>Step-by-step explanation:
Let X be the normal distribution
Kindly find attached a detailed annotation of the solution to the problem.
in the attached document, we found the value that corresponds to 80th percentile, hence we found the value such that the probability that the variable x is lower than this value is 0.8.
Also, from the calculation, we found that the value which corresponds to the 80th percentile is $1945
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The Solution.
Representing the problem in a diagram, we have
By formula,
In this case,
Substituting these values in the formula above, we get
Clearing the bracket, we get
Dividing both sides by 2, we get
Therefore, the correct answer is option C.
Answer:
(x - 3)² - 16 = 0
Step-by-step explanation:
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
Subtract 7 from both sides
x² - 6x + 7 = 0 ← in standard form
with a = 1, b = - 6
Given a quadratic in standard form then the x- coordinate of the vertex is
= -
= -
= 3
Substitute x = 3 into the equation for y
y = 3² - 6(3) - 7 = 9 - 18 - 7 = - 16 ⇒ (h, k) = (3, - 16)
y = (x - 3)² - 16 = 0