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3 years ago

What method is best to solve each equation?

Mathematics

1 answer:

Paladinen [302]3 years ago

7 0

It really depends on your preference of method

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A physicist examines 25 water samples for nitrate concentration. The mean nitrate concentration for the sample data is 0.165 cc/

xz_007 [3.2K]

Answer:

The 80% confidence interval for the the population mean nitrate concentration is (0.144, 0.186).

Critical value t=1.318

Step-by-step explanation:

We have to calculate a 80% confidence interval for the mean.

The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.

The sample mean is M=0.165.

The sample size is N=25.

When σ is not known, s divided by the square root of N is used as an estimate of σM:

$s_M=\dfrac{s}{\sqrt{N}}=\dfrac{0.078}{\sqrt{25}}=\dfrac{0.078}{5}=0.016$

The degrees of freedom for this sample size are:

$df=n-1=25-1=24$

The t-value for a 80% confidence interval and 24 degrees of freedom is t=1.318.

The margin of error (MOE) can be calculated as:

$MOE=t\cdot s_M=1.318 \cdot 0.016=0.021$

Then, the lower and upper bounds of the confidence interval are:

$LL=M-t \cdot s_M = 0.165-0.021=0.144\\\\UL=M+t \cdot s_M = 0.165+0.021=0.186$

The 80% confidence interval for the population mean nitrate concentration is (0.144, 0.186).

6 0

3 years ago

10. Find the slope and y-intercept of the line.<br> y = 7/5x - 3

myrzilka [38]

Answer:

slope = 7/5

y-int = -3

Step-by-step explanation:

this equation is in slope-intercept form. in thsi form, the slope will always be the coefficient of x, and the y-intercept will always be the last constant, or the "b" term (dont forget to include the negative!)

8 0

3 years ago

How do i check an equation for extraneous solutions?

Marina86 [1]

Example:

$\sqrt x(x+1)=0$

This suggests two solutions, $x=0$ and $x=-1$ .

However, upon plugging these solutions back into the equation, you get

$\sqrt0(0+1)=0(1)=0$

which checks out, but

$\sqrt{-1}(1-1)=0$

does not because $\sqrt x$ is defined only for $x\ge0$ (assuming you're looking for real solutions only). So, we call $x=-1$ an extraneous solution, and the complete solution set (over the real numbers) is $x=0$ .

7 0

3 years ago

Read 2 more answers

After adding an 8-pound box with 6 identical boxes, the box weighted 72 pounds. The equation is 6x + 8 = 72. What does X equal?

Marianna [84]

Answer: x = 10.6666666 or 10 2/3

Step-by-step explanation:

6x + 8 = 72

- 8 -8

6x = 64

6x/6 = 64/6

x = 10.6666666 aka 10 2/3