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3 years ago

Stephanie ran four laps around the school track in 7 minutes and 30 seconds. How many seconds per lap is that

Mathematics

2 answers:

madreJ [45]3 years ago

6 0

I got 112 seconds hopefully this helps u but sorry if it doesn't help u

Svetradugi [14.3K]3 years ago

3 0

112.5 seconds per lap. As you need to convert the minutes to seconds, 7 x 60 = 420 + 30 = 450

450/4 = 112.5

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Determine whether a probability distribution is given. If a probability distribution is given, find its mean and standard deviat

drek231 [11]

Answer:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 0*0.031 +1*0.156+ 2*0.313+3*0.313+ 4*0.156+ 5*0.031 = 2.5$

We can find the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 0^2*0.031 +1^2*0.156+ 2^2*0.313+3^2*0.313+ 4^2*0.156+ 5^2*0.031 =7.496$

And we can calculate the variance with this formula:

$Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246$

And the deviation is:

$Sd(X) = \sqrt{1.246}= 1.116$

Step-by-step explanation:

For this case we have the following probability distribution given:

X 0 1 2 3 4 5

P(X) 0.031 0.156 0.313 0.313 0.156 0.031

The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.

The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).

We can verify that:

$\sum_{i=1}^n P(X_i) = 1$

And $P(X_i) \geq 0, \forall x_i$

So then we have a probability distribution

We can calculate the expected value with the following formula:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 0*0.031 +1*0.156+ 2*0.313+3*0.313+ 4*0.156+ 5*0.031 = 2.5$

We can find the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 0^2*0.031 +1^2*0.156+ 2^2*0.313+3^2*0.313+ 4^2*0.156+ 5^2*0.031 =7.496$

And we can calculate the variance with this formula:

$Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246$

And the deviation is:

$Sd(X) = \sqrt{1.246}= 1.116$

6 0

3 years ago

If x to the power of 2 equals 196 what does x equal

natulia [17]

Answer:

Step-by-step explanation:

<h2><u>Solve for x</u></h2>

<u /> $x^{2} = 196$

this can be solved by square rooting 196

$x = \sqrt{196}$

x = 14

<h3><u>the value for x is 14</u></h3>

3 0

3 years ago

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guapka [62]

Answer:

The average speed of the plain was 800 miles/h

Step-by-step explanation:

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2 years ago

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Simplify 1/4(8x+16)+4x.

QveST [7]

Answer:

6x+4

Step-by-step explanation:

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3 years ago

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I need help with this problem and show your work plz thanks

coldgirl [10]

Well is just their sum, thus

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3 years ago