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Which phrases describe sedimentary rock?

daser333 [38]

Smooth, rough, hard or soft are common descriptions

3 0

3 years ago

During a routine check of the fluoride content of Gotham City\'s water supply, the following results were obtained from replicat

Aleksandr-060686 [28]

Answer:

The mean is $x=0.503\frac{mg}{L}$

The 90% confidence interval is:

$i_{0.90}=[0.492\frac{mg}{L},0.514\frac{mg}{L}]$

Explanation:

1. First organize the data:

$x_{1}=0.487$

$x_{2}=0.487$

$x_{3}=0.511$

$x_{4}=0.511$

$x_{5}=0.519$

As there are 5 data, the sample size (n) is n=5

2. Calculate the mean x:

The mean is calculated adding up all the data and divide them between the sample size.

$x=\frac{0.511+0.487+0.511+0.487+0.519}{5}$

$x=0.503\frac{mg}{L}$

3. Find 90% confidence interval.

The formula to find the confidence interval is:

$i_{0.90}=[x+/-z_{\frac{\alpha}{2}}*(\frac{d}{\sqrt{n}})]$ (Eq.1)

where x is the mean, d is the standard deviation and n is the sample size.

And

$1-\alpha=0.90$

$\alpha=0.10$

$\frac{\alpha}{2}=0.05$

$z_{0.05}=1.645$

4. Find the standard deviation

$d=\sqrt{\frac{(x_{1}-x)^{2}+(x_{2}-x)^{2}+(x_{3}-x)^{2}+(x_{4}-x)^{2}+(x_{5}-x)^{2}}{n-1}}$

$d=\sqrt{\frac{(0.487-0.503)^{2}+(0.487-0.503)^{2}+(0.511-0.503)^{2}+(0.511-0.503)^{2}+(0.519-0.503)^{2}}{4}}$

$d=\sqrt{\frac{(-0.016)^{2}+(-0.016)^{2}+(0.008)^{2}+(0.008)^{2}+(0.016)^{2}}{4}}$

$d=\sqrt{2.24*10^{-4}}$

$d=0.015$

5. Replace values in (Eq.1):

$i_{0.90}=[0.503+/-1.645*(\frac{0.015}{2.236})]$

For the addition:

$i_{0.90}=[0.503+1.645*(\frac{0.015}{2.236})]$

$i_{0.90}=0.514$

For the subtraction:

$i_{0.90}=[0.503-1.645*(\frac{0.015}{2.236})]$

$i_{0.90}=0.492$

The 90% confidence interval is:

$i_{0.90}=[0.492,0.514]$

4 0

3 years ago

What happens in a chemical reaction with the individual elements?

Gemiola [76]

Chemical reactions involve electrons and where they move (if they move).
Metal atoms (or elements) usually give away their outer shell electrons in reactions to become stabilised (creating positive ions). Non-metal atoms (or elements) usually gain electrons in order to become stable (negative ions). Some reactions involve covalent bonds, metallic bonds, ionic bonds etc., but at the base (no pun intended :D) of most chemical reactions it's just a matter of electrons moving around between atoms.

Hope it helps!

3 0

4 years ago

Help asappppppppppppppppppppp

galina1969 [7]

The answer should be 12 since 4 x 3 = 12

This is because ammonia is NH^3 and if it has a number before it you multiply it with the rest of the chemical equation.

I hope this helps

6 0

3 years ago

Read 2 more answers

Is this an aromatic hydrocarbon? Why or why not?

swat32

The correct answer is D

3 0

3 years ago

Read 2 more answers