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o-na [289]
2 years ago
9

The times of all 15 year olds who run a certain race are approximately normally distributed with a given mean mu = 18 sec and st

andard deviation sigma = 1.2 sec. what percentage of the runners have times less than 14.4 sec?
Mathematics
1 answer:
Maru [420]2 years ago
7 0

The percentage of runners that have times less than 14.4 seconds that is P(x<14.4) is 0.0013499 which is approximately = 0.15%.

<h2>What is standard deviation?</h2>

The standard deviation of a data set is defined as how the data is dispersed in relation to the mean.

From the question,

The raw time given (X) = 14.4 sec

The mean value(m) = 18sec

The standard deviation(d) = 1.2 sec

Using the formula,

z = X - m/ d

z= 14.4- 18/1.2

z = -3.6/1.2

z= -3

Using a Z table to find the percentage equivalent of P(x<14.4) is 0.0013499 which is approximately = 0.15%.

Therefore, the percentage of runners that have times less than 14.4 seconds that is P(x<14.4) is 0.0013499 which is approximately = 0.15%.

Learn more about standard deviation here:

brainly.com/question/475676

#SPJ4

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3 years ago
A ball is kicked upward with an initial velocity of 32 feet per second. The ball's height, h (in feet), from the ground is model
stellarik [79]

Answer:

1.        t = 0.995 s

2.       h = 15.92  ft

Step-by-step explanation:

First we have to look at the following formula

Vf = Vo + gt

then we work it to clear what we want

Vo + gt = Vf

gt = Vf - Vo

t = (Vf-Vo)/g

Now we have to complete the formula with the real data

Vo = 32 ft/s      as the statement says

Vf = 0     because when it reaches its maximum point it will stop before starting to lower

g = -32,16 ft/s²        it is a known constant, that we use it with the negative sign because it is in the opposite direction to ours

t = (0 ft/s - 32 ft/s) / -32,16 ft/s²

we solve and ...

t = 0.995 s

Now we will implement this result in the following formula to get the height at that time

h = (Vo - Vf) *t /2

h = (32 ft/s - 0 ft/s) * 0.995 s / 2

h = 32 ft/s * 0.995 s/2

h = 31.84 ft / 2

h = 15.92  ft

4 0
2 years ago
Help me please and thank you
Kisachek [45]

Answer:

12.5 un^2

Step-by-step explanation:

The formula for area of a trapezoid is (a+b)/2 *h

a and b are the shorter and longer bases respectively. H is height, you have both.

Simply plug it into the equation and find your answer.

(2.5+7.5)/2 *2.5 = 5*2.5 which is equal to 12.5. Add units.

8 0
3 years ago
Brad wants to buy flowers for his friend with $15. The daisies are $1 each and the roses are $3 each. He buys 3 more daisies tha
melisa1 [442]
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d = r + 3

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d = r + 3
d = 3 + 3
d = 6....he bought 6 daisies, at $ 1 per daisy = $ 6
6 0
3 years ago
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A dataset shows that, on average, smokers do not live as long as nonsmokers and heavy smokers do not live as long as light smoke
leva [86]
<span>Given that A dataset shows that, on average, smokers do not live as long as nonsmokers and heavy smokers do not live as long as light smokers.

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