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3 years ago

15

the temperature at 3 p.m. was 35 Fahrenheit. the temperature had dropped 45 degrees by 9 p.m. . what's the temperature in degree

s Fahrenheit at 9 p.m.?

1 answer:

NARA [144]3 years ago

4 0

-15 degrees Fahrenheit

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The accompanying data on x = current density (mA/cm2) and y = rate of deposition (m/min)μ appeared in a recent study.

gtnhenbr [62]

Answer:

a) $r=\frac{4(333)-(200)(5.37)}{\sqrt{[4(12000) -(200)^2][4(9.3501) -(5.37)^2]}}=0.9857$

The correlation coefficient for this case is very near to 1 so then we can ensure that we have linear correlation between the two variables

b) $m=\frac{64.5}{2000}=0.03225$

Now we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{200}{4}=50$

$\bar y= \frac{\sum y_i}{n}=\frac{5.37}{4}=1.3425$

$b=\bar y -m \bar x=1.3425-(0.03225*50)=-0.27$

So the line would be given by:

$y=0.3225 x -0.27$

Step-by-step explanation:

Part a

The correlation coeffcient is given by this formula:

$r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}$

For our case we have this:

n=4 $\sum x = 200, \sum y = 5.37, \sum xy = 333, \sum x^2 =12000, \sum y^2 =9.3501$

$r=\frac{4(333)-(200)(5.37)}{\sqrt{[4(12000) -(200)^2][4(9.3501) -(5.37)^2]}}=0.9857$

The correlation coefficient for this case is very near to 1 so then we can ensure that we have linear correlation between the two variables

Part b

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=12000-\frac{200^2}{4}=2000$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=333-\frac{200*5.37}{4}=64.5$

And the slope would be:

$m=\frac{64.5}{2000}=0.03225$

Now we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{200}{4}=50$

$\bar y= \frac{\sum y_i}{n}=\frac{5.37}{4}=1.3425$

And we can find the intercept using this:

$b=\bar y -m \bar x=1.3425-(0.03225*50)=-0.27$

So the line would be given by:

$y=0.3225 x -0.27$

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3 years ago

The graph shows the relationship between the number of apples and their cost. For the point (1, r), what is the value of r?

3241004551 [841]

Answer:

C.

Step-by-step explanation:

When you check the point that is on X, it is a little over halfway to the point 1,2. It would be like 1,1.5 or 1,1.6.

5/3 is the equivalent to 1.6 so that answer would make the most sense.

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What is the slope of the line that passes through the points (6, -5) and (6, -8)?

Anni [7]

(6,-5) (6,-8)

y2-y1/x2-x1

-8+5/6-6

-3/0

Undefined should be the answer. Hope this helped (:

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3 years ago

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san4es73 [151]

Answer:

Step-by-step explanation:

10 x 3 = $30

10 x 4 = $12

$30 + $12 = $42 in think thats the answer i havent been to school in a while

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Dennis_Churaev [7]

Answer:

y = -2x+4

Step-by-step explanation:

the equation of the line there is: y = -2x+8

The parallel line to this one should have the same slope as the first one(-2x)

Parallel lines always have the same slopes

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