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What is the Identity Property of Multiplication?

Scilla [17]

Answer:

The identity property of multiplication, also called the multiplication property of one says that a number does not change when that number is multiplied by 1. Ex. 12x1=12

7 0

2 years ago

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The American Water Works Association reports that the per capita water use in a single-family home is 63 gallons per day. Legacy

Debora [2.8K]

Answer:

$t=\frac{60-63}{\frac{8.9}{\sqrt{28}}}=-1.784$

$df=n-1=28-1=27$

$p_v =P(t_{(27)}$

If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to fail reject the null hypothesis, so we can't conclude that the true mean is less than 63 gallons per day at 1% of signficance.

Step-by-step explanation:

Data given and notation

$\bar X=60$ represent the sample mean

$s=8.9$ represent the sample standard deviation

$n=28$ sample size

$\mu_o =68$ represent the value that we want to test

$\alpha=0.01$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the true mean is less than 63, the system of hypothesis would be:

Null hypothesis: $\mu \geq 63$

Alternative hypothesis: $\mu < 63$

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{60-63}{\frac{8.9}{\sqrt{28}}}=-1.784$

P-value

The first step is calculate the degrees of freedom, on this case:

$df=n-1=28-1=27$

Since is a one side lower test the p value would be:

$p_v =P(t_{(27)}$

Conclusion

If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to fail reject the null hypothesis, so we can't conclude that the true mean is less than 63 gallons per day at 1% of signficance.

5 0

3 years ago

A line is tangent to the circle x^2+y^2=41, at the point (-4,-5)

VashaNatasha [74]

If the equation of the circle is x^2+ y^2 = 41, we must first understand the parts of the equation.
A general circle's equation is (x-h)^2+(y-k)^2= r^2
(h.k) is the radius of the circle
r is the radius of the circle
Another useful fact to know is that tangent lines touch the circle at one point (4,5)

Since in our original equation there are no h or k values, we can assume that the center of the circle is (0,0).

The formula for slope is Y1-Y2
X1-X2
We can break this down with our two points (center and tangent)
(0,0) and (-4,-5)
(X1,Y1) and (X2,Y2)

therefore, we will put the equation as such
0-(-5)= 5 = 5
0-(-4)= 4  4

this is our slope from the center to the point of tangency.

We know that tangent lines are perpendicular to the radius, which we've already found the slope of. Perpendicular lines are opposite reciprocals of the line they are perpendicular to.

Therefore, we take our slope from center to the tangent, and make it opposite and then take the reciprocal of that slope, which will give us the slope of the tangent line itself. (note: reciprocal means flip the numerator and denominator)
5 = -5 = -4
4 4 5

Now, we have a point on the line, and the line's slope. We can use slope-intercept equation to find the equation of the line.

Slope-int y=mx+b
(x,y) is a point,
m is the slope
b is the y intercept ( the point where x=0, or where its on the y axis)

now we plug things in
(-4,-5) is our point,
-4 is our slope
5

-5=-4(-4)+b After we plug things in, solve for b
5

-5= 3.2+b

-1.8= b or b= 1 4
5

Now we just need to rewrite our equation with all our components.
(-4.-5) = point
-4 = slope
5
1 4 = y-intercept
 5

y=-4 x+ 1 4 This is the equation of the tangent line
 5 5

Hope that helped

7 0

3 years ago

What is the equation of a line that passes through the point (1, 8) and is perpendicular to the line whose equation is y=x/2+3 ?

Kipish [7]

-4x/5+8.8. I think that's it, and if it isn't, i don't know.

4 0

3 years ago

Write each function in standard form. y = 3(x - 2)2^2- 4

galben [10]

Answer:

-4

Step-by-step explanation:

7 0

3 years ago