Solve for x and y
1 answer:
Answer:
x = 2√2
y = 2√6
Step-by-step explanation:
Consider the ratio of the two legs of the two smaller interior right triangles. (refer to attached diagrams for the triangles - I have outlined one in blue and the other in red)
These will be equal since the triangles are similar
shorter leg : longer leg
(blue triangle = red triangle)
⇒ x : 4 = 2 : x
⇒ x/4 = 2/x
⇒ x² = 8
⇒ x = √8
⇒ x = 2√2
Now we have x, we have the two legs of the right triangle with hypotenuse labelled y.
Using Pythagoras' Theorem a² + b² = c² (where a and b are the legs and c is the hypotenuse)
⇒ 4² + (2√2)² = y²
⇒ y² = 24
⇒ y = √24
⇒ y = 2√6
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Answer:
(a): The 95% confidence interval is (46.4, 53.6)
(b): The 95% confidence interval is (47.9, 52.1)
(c): Larger sample gives a smaller margin of error.
Step-by-step explanation:
Given
-- sample size
-- sample mean
--- sample standard deviation
Solving (a): The confidence interval of the population mean
Calculate the standard error
The 95% confidence interval for the z value is:
Calculate margin of error (E)
The confidence bound is:
--- approximated
--- approximated
<em>So, the 95% confidence interval is (46.4, 53.6)</em>
Solving (b): The confidence interval of the population mean if mean = 90
First, calculate the standard error of the mean
The 95% confidence interval for the z value is:
Calculate margin of error (E)
The confidence bound is:
--- approximated
--- approximated
<em>So, the 95% confidence interval is (47.9, 52.1)</em>
Solving (c): Effect of larger sample size on margin of error
In (a), we have:
In (b), we have:
<em>Notice that the margin of error decreases when the sample size increases.</em>