Can someone please help me?
1 answer:
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The area of the room is square feet so Michelle's reasoning was incorrect.
Step-by-step explanation:
Step 1:
To calculate the area of the given room, we divide the unknown shape into known shapes.
The room's shape is made of 2 rectangles.
The area of a rectangle is the product of its length and its width.
One rectangle has a length of 10 feet and a width of feet.
The other rectangle has a length of feet and a width of
feet.
Step 2:
The area of the first rectangle square feet.
The area of the second rectangle square feet.
The total area of the room square feet.
The area of the room is square feet so Michelle's reasoning was incorrect.
Answer:
d. The interval contains only negative numbers. We cannot say at the required confidence level that one region is more interesting than the other.
Step-by-step explanation:
Hello!
You have the data of the chemical measurements in two independent regions. The chemical concentration in both regions has a Gaussian distribution.
Be X₁: Chemical measurement in region 1 (ppm)
Sample 1
n= 12
981 726 686 496 657 627 815 504 950 605 570 520
μ₁= 678
σ₁= 164
Sample mean X[bar]₁= 678.08
X₂: Chemical measurement in region 2 (ppm)
Sample 2
n₂= 16
1024 830 526 502 539 373 888 685 868 1093 1132 792 1081 722 1092 844
μ₂= 812
σ₂= 239
Sample mean X[bar]₂= 811.94
Using the information of both samples you have to determina a 90% CI for μ₁ - μ₂.
Since both populations are normal and the population variances are known, you can use a pooled standard normal to estimate the difference between the two population means.
[(X[bar]₁-X[bar]₂)±*
]
[(678.08-811.94)±1.648*]
[-259.49;-8.23]ppm
Both bonds of the interval are negative, this means that with a 90% confidence level the difference between the population means of the chemical measurements of region 1 and region 2 may be included in the calculated interval.
You cannot be sure without doing a hypothesis test but it may seem that the chemical measurements in region 1 are lower than the chemical measurements in region 2.
I hope it helps!
9514 1404 393
Answer:
136
Step-by-step explanation:
The attached chart shows the result of using the numbers in the problem statement to calculate the percentage of the population in each category.
95% accuracy on infected individuals is assumed to mean that 95% of the 2% who are infected return a positive test result. The other 5% return a negative test result.
Similarly, 90% accuracy on uninfected individuals is assumed to mean that 90% of the 98% who are not infected will return a negative test result, and the remaining 10% of those 98% will return a (false) positive test result.
Then of the 11.7% who return a positive test result, only 1.9% are actually infected. This fraction is a/b = 19/117, so ...
a + b = 19 + 117 = 136
_____
<em>Additional comment</em>
When forming ratios of percentages, one must be very clear about the base of the percentage. Above, the base for every percentage is the entire population of mathletes. The fraction 19/117 is the fraction of those who tested positive that are actually infected (about 16.2% of positives).
