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Ray Of Light [21]

3 years ago

12

Given a normal distribution with a mean of 128 and a standard deviation of 15, what percentage of values is with an interval 83

to 173?
A.32%
B.50%
C.68%
D.95%
E.99.7%

Brainiest and 90+ points!

1 answer:

max2010maxim [7]3 years ago

3 0

Answer:C. 68%

Step-by-step explanation:

<u>hope this helps :) - [email protected] </u>

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I need to solve y=2x-4 solve for y algebraically? That for y

SOVA2 [1]

Answer:

x=3 y=2

Step-by-step explanation:

please refer to the picture I sent

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3 years ago

What is the volume of the cone if the height is 16cm and the radius is 17cm?

V125BC [204]

Ignore the stricked out and for this, you just use the vol. of cone formula.

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3 years ago

Danny earns a monthly allowance of twenty dollars and extra seventy five cents every time he is nice to his mom. Avery earns a m

Lerok [7]

Answer:

Danny: y-=.75x+20

Avery: y=1.25x+18

Step-by-step explanation:

To write a system of equations, it usually equals y=mx+b. Since Danny and Avery both earn the set monthly allowance of 20 and 18 dollars respectively, those numbers go on the variable b since it's a set amount and they start off with that amount of money if they weren't nice to their mom at all.

Since we are trying to find the overall amount of money, let y=total money a child earns every month and x=how many times the child is nice to their mother.

The extra .75 cents Danny earns go under the variable m because it is dependent on how many times he is nice to his mom. Along with Avery.

4 0

2 years ago

Show that if X is a geometric random variable with parameter p, then

Lubov Fominskaja [6]

Answer:

$\sum_{k=1}^{\infty} \frac{p(1-p)^{k-1}}{k}=-\frac{p ln p}{1-p}$

Step-by-step explanation:

The geometric distribution represents "the number of failures before you get a success in a series of Bernoulli trials. This discrete probability distribution is represented by the probability density function:"

$P(X=x)=(1-p)^{x-1} p$

Let X the random variable that measures the number os trials until the first success, we know that X follows this distribution:

$X\sim Geo (1-p)$

In order to find the expected value E(1/X) we need to find this sum:

$E(X)=\sum_{k=1}^{\infty} \frac{p(1-p)^{k-1}}{k}$

Lets consider the following series:

$\sum_{k=1}^{\infty} b^{k-1}$

And let's assume that this series is a power series with b a number between (0,1). If we apply integration of this series we have this:

$\int_{0}^b \sum_{k=1}^{\infty} r^{k-1}=\sum_{k=1}^{\infty} \int_{0}^b r^{k-1} dt=\sum_{k=1}^{\infty} \frac{b^k}{k}$ (a)

On the last step we assume that $0\leq r\leq b$ and $\sum_{k=1}^{\infty} r^{k-1}=\frac{1}{1-r}$ , then the integral on the left part of equation (a) would be 1. And we have:

$\int_{0}^b \frac{1}{1-r}dr=-ln(1-b)$

And for the next step we have:

$\sum_{k=1}^{\infty} \frac{b^{k-1}}{k}=\frac{1}{b}\sum_{k=1}^{\infty}\frac{b^k}{k}=-\frac{ln(1-b)}{b}$

And with this we have the requiered proof.

And since $b=1-p$ we have that:

$\sum_{k=1}^{\infty} \frac{p(1-p)^{k-1}}{k}=-\frac{p ln p}{1-p}$

4 0

3 years ago

You start driving north for 9 miles, turn right, and drive east for another 40 miles. At the end of driving, what is your straig

Vsevolod [243]

The straight line distance from the starting point is 41 miles.

<u>Explanation:</u>

Given:

Distance covered towards north, n = 9 miles

Distance covered towards east, e = 40 miles

Distance from the origin to the end, x = ?

If we imagine this, then the route forms a right angle triangle

where,

n is the height

e is the base

x is the hypotenuse

Using pythagoras theorm:

(x)² = (n)² + (e)²

(x)² = (9)² + (40)²

(x)² = 1681

x = 41 miles

Therefore, the straight line distance from the starting point is 41 miles.

5 0

2 years ago