im stuck on this question ​

Answer:

The minimum number of samples required is 487.

Step-by-step explanation:

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1 - 0.95}{2} = 0.025[/tex]

Now, we have to find z in the Ztable as such z has a pvalue of [tex]1 - \alpha[/tex].

That is z with a pvalue of [tex]1 - 0.025 = 0.975[/tex], so Z = 1.96.

Now, find the margin of error M as such

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.

Standard deviation 4.5 mg/L.

This means that [tex]\sigma = 4.5[/tex]

What is the minimum number of samples required to estimate today's level to within 0.4 mg/L with 95% confidence?

This is n for which M = 0.4. So

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

[tex]0.4 = 1.96\frac{4.5}{\sqrt{n}}[/tex]

[tex]0.4\sqrt{n} = 1.96*4.5[/tex]

[tex]\sqrt{n} = \frac{1.96*4.5}{0.4}[/tex]

[tex](\sqrt{n})^2 = (\frac{1.96*4.5}{0.4})^2[/tex]

[tex]n = 486.2[/tex]

Rounding up

The minimum number of samples required is 487.

Answer:

it's letter D. cos 16⁰=²¹--x

Answer:

The answer is 4ws - 12

Step-by-step explanation:

1) Collect like terms.

[tex]4ws + (4 - 16)[/tex]

2) Simplify.

[tex]4ws - 12[/tex]

therefor, the answer is 4ws - 12.

Answer:

u already got it cos x = 8f

Step-by-step explanation:

Answer:

German Test

Step-by-step explanation:

Find common denominator:

34/50=68/100

14/20=70/100

Therefore, Abeer did better on the German test as 14/20>34/50

Answer:

exponent

Step-by-step explanation:

Answer:

power or exponent it can be both, but being specific here, choose exponent

Step-by-step explanation:

i studied this concept trust me

Answer:

27 cubic units

Step-by-step explanation:

A cube has equal dimensions. So the volume is 3units × 3units × 3units or 27cubic units

Answer: 1324 in^2

Step-by-step explanation:

Answer:

4/35

Step-by-step explanation:

Probability of 1 student having no hw is 4/7, then 3/6, then 2/5

4/7 x 3/6 x 2/5 reduces to 4/35

Answer:

Angle YXU is equal to 113 degrees. those are supplementary angles

Step-by-step explanation:

Answer:

3. B

4. 29, 33

Step-by-step explanation:

Answer:

B

Step-by-step explanation:

Substitute the coordinates of the point into the left side of the equation and if the value obtained equals the right side then it is a solution.

A (- 4, 4 )

- 3(- 4) - 4 = 12 - 4 = 8 ≠ 6 ← not a solution

B (- 3, 3 )

- 3(- 3) - 3 = 9 - 3 = 6 ← this is a solution

The result is B

Answer:

Area= 840

Step-by-step explanation:

Area= (20x13)x2+(10x12x1/2)x2+10x20

=520+120+200

=840

Answer:

5/x = 7/x-4

5(x-4) = 7(x)

5x - 20 = 7x

5x - 7x = 20

-2x = 20

x = -20/2 = -10

Answer:

Rational

√36

=6

plz mark me as brainliest

Answer:  Rational

Step-by-step explanation:  

= /36

= 6

Can you give me a thank you?

9514 1404 393

Answer:

  ∆BCR ≅ ∆BAR

  x = 6

Step-by-step explanation:

For congruence, define point R where the altitude line meets segment AC.

The diagram shows you AR ≅ RC. You know BR ≅ BR by the reflexive property, and you know that ∠BRC ≅ ∠BRA = 90°. You can therefore claim ...

  ∆BCR ≅ ∆BAR . . . . by the SAS congruence postulate

__

To solve for x, you don't need to show congruence of the right triangles. You only need to realize that the markings on segment AC show the left half is the same length (x) as the right half. The Pythagorean theorem is used to find x.

  x² +8² = 10²

  x² = 100 -64 = 36

  x = √36 = 6

The length of x is 6 units.

_____

As you can see here, an altitude that is a median divides the isosceles triangle into two congruent right triangles. (That altitude also bisects angle B.)

You may recognize that the side ratios in the right triangle are 8:10 = 4:5. The missing side completes the Pythagorean triple 3:4:5, so is 2·3 = 6 = x.

Answer:

x = 1

Step-by-step explanation:

Given the matrix;

[tex]-2\left[\begin{array}{ccc}x&-1\\3&5\end{array}\right] + \left[\begin{array}{ccc}3&8\\-1&6\end{array}\right] = \left[\begin{array}{ccc}x&10\\-7&-4\end{array}\right][/tex]

Converting to equations

From the first row of each matrices

-2x + 3 = x

Collect the like terms

-2x - x = -3

-3x = -3

x = -3/-3

x = 1

Hence the value of x is 1

Answer:

the correct answer is first graph because melting decreases by straight lines and goes down and the one you choose is not correct because you are not gonna have melting stops for a while (✿ ♡‿♡)

Answer:

The formula for circumference of a circle is

2pi,R.

In which R= radius. Then we Insert 18 in for the circumstances.

so, 18=2πr

then solving for r

18=2

÷. ÷

2. 2

R = 9,,

Answer

A

Step-by-step explanation:

So in the diagrams we see there is 2/3 shaded into a 12  cutted square. So we multiply 4x3 to get 12. So now we have to turn the 3 into 12.

so

[tex]\frac{2}3}[/tex] x[tex]\frac{4}{4}[/tex] =[tex]\frac{8}{12}[/tex]

Since we multiplied 4 on the bottom we have to multiply 4 on the top.

sorry im not good at explaining but if you need me to re explain ill work on it. :)

Answer:

[tex]y=-\frac{1}{2} x-3[/tex]

Step-by-step explanation:

Hi there!

Slope intercept form: [tex]y=mx+b[/tex] where m is the slope of the line and b is the y-intercept (the value of y when the line crosses the y-axis)

1) Determine the slope

The slope of a line is the same as its [tex]\frac{rise}{run}[/tex], or in other words, the number of units the line moves upwards over the number of units the line moves to the right.

In the graph, we can see that for every 2 units it moves right, it moves down 1 units. Therefore, our slope is [tex]-\frac{1}{2}[/tex]. This is negative since it is traveling downwards.

Plug [tex]-\frac{1}{2}[/tex] into [tex]y=mx+b[/tex] as m:

[tex]y=-\frac{1}{2} x+b[/tex]

2) Determine the y-intercept

In the graph, we can see that the line crosses the y-axis when y is equal to -3. Plug -3 into [tex]y=-\frac{1}{2} x+b[/tex] as b:

[tex]y=-\frac{1}{2} x-3[/tex]

I hope this helps!

Answer:

4:3

Step-by-step explanation:

He has 4 Soccer Medals, 3 Swimming Medals

So it would be 4:3

Answer:

Step-by-step explanation:

18 tiles and 10 shaded in

I think the answer is C

9514 1404 393

Answer:

  angle L = 106°

Step-by-step explanation:

Opposite angles in an inscribed quadrilateral are supplementary.

  ∠L = 180° -∠N

  ∠L = 180° -74° = 106°

Answer:

the answer is step 2 I hope it's help

Answer:

9

Step-by-step explanation:

5x - 27 / - 3 = - 6

5x - 27 = - 6 x ( - 3 )

5x - 27 = 18

5x = 18 + 27

5x = 45

x = 45 / 5

x = 9