The answer to this question pleas

To decrease the impact on the environment, factory chimneys must be high enough to allow pollutants to dissipate over a larger a

Komok [63]

Answer:

The probability hat the sample mean height for the 40 chimneys is greater than 102 meters is 0.1469.

Step-by-step explanation:

Let the random variable X be defined as the height of chimneys in factories.

The mean height is, μ = 100 meters.

The standard deviation of heights is, σ = 12 meters.

It is provided that a random sample of n = 40 chimney heights is obtained.

According to the Central Limit Theorem if we have an unknown population with mean μ and standard deviation σ and appropriately huge random samples (n > 30) are selected from the population with replacement, then the distribution of the sample means will be approximately normally distributed.

Then, the mean of the distribution of sample means is given by,

$\mu_{\bar x}=\mu$

And the standard deviation of the distribution of sample means is given by,

$\sigma_{\bar x}=\frac{\sigma}{\sqrt{n}}$

Since the sample selected is quite large, i.e. n = 40 > 30, the central limit theorem can be used to approximate the sampling distribution of sample mean heights of chimneys.

$\bar X\sim N(\mu_{\bar x},\ \sigma^{2}_{\bar x})$

Compute the probability hat the sample mean height for the 40 chimneys is greater than 102 meters as follows:

$P(\bar X>102)=P(\frac{\bar X-\mu_{\bar x}}{\sigma_{\bar x}})>\frac{102-100}{12/\sqrt{40}})$

$=P(Z>1.05)\\=1-P(Z$

*Use a z-table fr the probability.

Thus, the probability hat the sample mean height for the 40 chimneys is greater than 102 meters is 0.1469.

8 0

3 years ago

Ramiro earns $20 per hour during the week and $30 per hour for overtime on the weekends. One week Ramiro earned a total of $650.

nika2105 [10]

Answer:

Week=25 Hours

Weekend= 5 Hours

Step-by-step explanation:

So we need to use the info they gave us and create two equations. Firstly we know how much he gets paid per hour during the week (x) and how much he gets paid on the weekend (y).

$20x+$30y=$650

We get this because we know the combined rates he is paid times the hours should add up to the amount he earned.

The next equation will be made off of the information that he worked 5 times as many hours during the week as on the weekend. This tells us that we will take the weekend hours (y) and multiply them by 5 in order to get the week hours (x).

x=5y Now, since we have one variable by itself, we can plug it in for x in the first equation.

20(5y)+30y=650 Our first step here is to distribute the 20 to the 5y in order to eliminate the parenthesis.

100y+30y=650 Next add the like terms together (100y+30y).

Now all we have to do to find y is divide by 130 on both sides to get y alone.

130y=650

________

130 130

y=5 Now to solve for x we just plug our y value into one of the equations above. I'm going to use the second equation.

x=5(5)

x=25

3 0

3 years ago