What is 7200 minutes, in days? (Remember, there are 60 minutes in an hour and 24 hours in a day.)

A state administered standardized reading exam is given to eighth grade students. The scores on this exam for all students state

Lorico [155]

Answer:

$a=502 +1.28*81=605.68$

So the value of height that separates the bottom 90% of data from the top 10% is 605.68.

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the heights of a population, and for this case we know the distribution for X is given by:

$X \sim N(502,81)$

Where $\mu=502$ and $\sigma=81$

We want to find a value a, such that we satisfy this condition:

$P(X>a)=0.1$ (a)

$P(X$ (b)

Both conditions are equivalent on this case. We can use the z score again in order to find the value a.

As we can see on the figure attached the z value that satisfy the condition with 0.9 of the area on the left and 0.1 of the area on the right it's z=1.28. On this case P(Z<1.28)=0.9 and P(z>1.28)=0.1

If we use condition (b) from previous we have this:

$P(X$

$P(z$

But we know which value of z satisfy the previous equation so then we can do this:

$z=1.28$

And if we solve for a we got

$a=502 +1.28*81=605.68$

So the value of height that separates the bottom 90% of data from the top 10% is 605.68.

3 0

3 years ago

Help plz 40x + 100 >500

serg [7]

Answer:

x > 10

Step-by-step explanation:

Isolate the variable by dividing each side by factors that don't contain the variable.

8 0

3 years ago

Put me out of my misery! Help me! If possible could you show me how to do this?

prisoha [69]

Answer:

4

4z+4

Divide each term of 4z+4 by 4 to get 1+z.

1+z

8 0

2 years ago

Read 2 more answers

1. y = x2 + 8x + 15 Find the zeros of the function by rewriting the function in intercept form

lubasha [3.4K]

The zeros of given function $y=x^{2}+8 x+15$ is – 5 and – 3

Solution:

$\text { Given, equation is } y=x^{2}+8 x+15$

We have to find the zeros of the function by rewriting the function in intercept form.

By using intercept form, we can put value of y as to obtain zeros of function

We know that, intercept form of above equation is $x^{2}+8 x+15=0$

$\text { Splitting } 8 x \text { as }(5+3) x \text { and } 15 \text { as } 5 \times 3$

$\begin{array}{l}{\rightarrow x^{2}+(5+3) x+5 \times 3=0} \\\\ {\rightarrow x^{2}+5 x+3 x+5 \times 3=0}\end{array}$

Taking “x” as common from first two terms and “3” as common from last two terms

x (x + 5) + 3(x + 5) = 0

(x + 5)(x + 3) = 0

Equating to 0 we get,

x + 5 = 0 or x + 3 = 0

x = - 5 or – 3

Hence, the zeroes of the given function are – 5 and – 3

5 0

3 years ago

Can someone please help me with this question

zlopas [31]

Answer:

15 kilometers

Step-by-step explanation:

So we know:

For 4 days she runs 1500 meters each day.

For 3 days she runs 3 kilometers each day.

First off, lets convert 1500 meters into kilometers.

There are 1000 meters in a kilometer, so pluggin in 1500 meters:

1500/1000 = 1.5

So for 4 days she runs 1.5 kilometers each day.

Now, to find the total kilometers, we must find multiply the 1.5 kilometers by the 4 days, the 3 kilometers by the 3 days, then add those two together.

So lets do this:

1.5*4 = 6

So she ran 6 kilometers in the first 4 days.

Next we have:

3*3 = 9

So she ran 9 kilometers in the last 3 days.

Now finally add them together:

6 + 9 = 15

So she ran a total of 15 kilometers.

Hope this helps!

7 0

3 years ago