N+5n=30 what does n equal

Round the fraction or mixed number to the nearest 1/2 ( each one)

MAXImum [283]

1, 4, 100 1/2, 4 1/2, 5

3 0

3 years ago

A population has a mean of 200 and a standard deviation of 50. Suppose a sample of size 100 is selected and x is used to estimat

zmey [24]

Answer:

a) 0.6426 = 64.26% probability that the sample mean will be within +/- 5 of the population mean.

b) 0.9544 = 95.44% probability that the sample mean will be within +/- 10 of the population mean.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

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.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this question, we have that:

$\mu = 200, \sigma = 50, n = 100, s = \frac{50}{\sqrt{100}} = 5$

a. What is the probability that the sample mean will be within +/- 5 of the population mean (to 4 decimals)?

This is the pvalue of Z when X = 200 + 5 = 205 subtracted by the pvalue of Z when X = 200 - 5 = 195.

Due to the Central Limit Theorem, Z is:

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

X = 205

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

$Z = \frac{205 - 200}{5}$

$Z = 1$

$Z = 1$ has a pvalue of 0.8413.

X = 195

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

$Z = \frac{195 - 200}{5}$

$Z = -1$

$Z = -1$ has a pvalue of 0.1587.

0.8413 - 0.1587 = 0.6426

0.6426 = 64.26% probability that the sample mean will be within +/- 5 of the population mean.

b. What is the probability that the sample mean will be within +/- 10 of the population mean (to 4 decimals)?

This is the pvalue of Z when X = 210 subtracted by the pvalue of Z when X = 190.

X = 210

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

$Z = \frac{210 - 200}{5}$

$Z = 2$

$Z = 2$ has a pvalue of 0.9772.

X = 195

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

$Z = \frac{190 - 200}{5}$

$Z = -2$

$Z = -2$ has a pvalue of 0.0228.

0.9772 - 0.0228 = 0.9544

0.9544 = 95.44% probability that the sample mean will be within +/- 10 of the population mean.

7 0

3 years ago

The volume of a cube depends on the length of its sides. This can be written

White raven [17]

Answer:

Step-by-step explanation:

The given question is that the volume of a cube depends on the length of its sides.This can be written in function notation as v(s). What is the best interpretation of v(3)=27.

Solution:

According to the question the volume of a cube depends on the length of its sides. According to the statement we will apply the formula of volume of a cube.

V(s)=s³

In this question we have given s=3ft.

So, we will put the value of 's' in the formula.

V(s)=s³

V(3)=3³

Multiply 3 three times to get the answer.

V(3)=3*3*3

V(3)=27 ft³

This means that the cube has a volume of 27ft³ with the length of its sides 3ft....

8 0

4 years ago

Una parte de 25 000 dólares se invierte al 10% de interés, otra parte al 12 % y el resto al 16%. El ingreso anual total de las t

Drupady [299]

Answer:

$5000 at 10%, $10000 at 12% and 10000 at 16%

Step-by-step explanation:

One part of $ 25,000 is invested at 10% interest, another part at 12%, and the rest at 16%. The total annual income from the three investments is $ 3,200. Also, the income from the investment at 16% is equal to the income from the other two investments combined. How much was invested at each interest rate?

==================

Let the parts be x, y and z

As per given we get below system of equations:

x + y + z = 25000
0.1x + 0.12y + 0.16z = 3200
0.1x + 0.2y = 0.16z

Substitute 0.1x + 0.2y in the second equation:

0.16z + 0.16z = 3200
0.32z = 3200
z = 3200/0.32
z = 10000

Now we have:

x + y + 10000 = 25000 ⇒ x + y = 15000

and

0.1x + 0.12y + 0.16*10000 = 3200 ⇒ 0.1x + 0.12y = 1600

Multiply the second equation and then subtract the first one:

10(0.1x + 0.12y) = 10(1600) ⇒ x + 1.2y = 16000
x + 1.2y - (x + y) = 16000 - 15000
0.2y = 1000
y = 10000

Then

x = 15000 - 10000 = 5000

So the parts are:

$5000 at 10%, $10000 at 12% and 10000 at 16%

4 0

3 years ago

What is the solution to this system: 4x+9y=28 - 4x-y=-28

Degger [83]

Answer:

x = 7

y = 0

Step-by-step explanation:

→To solve this, you can use the elimination method. To do this, you must have one set of variables that can cancel each other out. In the problem given, we already have positive 4x and -4x, making them cancel out:

4x + 9y = 28

-4x - y = -28

__________

8y = 0

y = 0

→Plug in 0 for y, into an equation:

-4x - 0 = -28

-4x = -28

x = 7

6 0

3 years ago