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2 years ago

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At a high school the average grade for the first semester for all subjects was 79.3. Based on this mean , the principal conclude

s that half of the grades were 79.3. Higher is her conclusion justified? Why or why not?

1 answer:

svet-max [94.6K]2 years ago

4 0

Answer:

That is incorrect. It would be appropriate if the median were 79.3, since the median is the value in the middle (when placing the data in order).

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How can I find the volume of a cone 9 radius and 18 height

Anastasy [175]

Answer:

V = 486 $\pi$ , or approx. 1,526.814

Step-by-step explanation:

V = $\pi$ *r²*(h/3)

plug in the numbers: V = $\pi$ * (9)² * (18/3)

simplify: V = $\pi$ * 81 * 6

simplify: V = 486 $\pi$ , or approx. 1,526.814

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2 years ago

Read 2 more answers

Elliott is standing at the top of a store escalator that leads to the ground floor below. the angle of depression from the top o

erma4kov [3.2K]

By using what we know about right triangles, we conclude that the height is 11ft.

<h3>How far is the top of the escalator from the ground floor? </h3>

We can think of this as a right triangle.

Where the length of the escalator is the hypotenuse

We know that the angle of depression is 42.51°, then the top angle of our right triangle is:

90° - 42.51° = 47.49°

Now, the height of the top of the escalator would be the adjacent cathetus to said angle, then we can use the relation:

cos(a) = (adjacent cathetus)/(hypotenuse)

Replacing what we know:

cos(47.49°) = height/16ft

cos(47.49°) *16ft = height = 10.8ft

Rounding to the nearest foot, we get:

height = 11ft

If you want to learn more about right triangles:

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1 year ago

Round number to nearest hundred 1,427 as 1,420. 68,136 as 68,130. 271,308 as 271,300. 7,593,656 as 7,594,000 right?

xenn [34]

Normally to round a number to the nearest hundred you want to go to the hundreds column for example:
1427
1...thousand, 4...hundred, 2...tenth, and 7... ones so this one would be 1400
68136=68100 and so on.... hope this helps

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2 years ago

On a piece of paper, graph y = -x2 + 4x - 3 and identify the zeros. Then determine which answer choice matches the graph that yo

zlopas [31]

Answer:

C. 1 and 3

Step-by-step explanation:

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2 years ago

Running times for 400 meters are Normally distributed for young men between 18 and 30 years of age with a mean of 93 seconds and

Nikolay [14]

Answer:

To be in the top 1% of the runners, the man has to run the 400 meters in at most 55.768 seconds.

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this question, we have that:

$\mu = 93, \sigma = 16$

How fast does a man have to run to be in the top 1% of runners?

The lower the time, the faster they are. So the man has to be at most in the 1st percentile, which is X when Z has a pvalue of 0.01. So he has to run in at most X seconds, and X is found when Z = -2.327. Then

$Z = \frac{X - \mu}{\sigma}$

$-2.327 = \frac{X - 93}{16}$

$X - 93 = -2.327*16$

$X = 55.768$

To be in the top 1% of the runners, the man has to run the 400 meters in at most 55.768 seconds.

8 0

2 years ago