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3 years ago

Need help with some practice questions since all are different types I'm asking alot sorry!

Mathematics

1 answer:

sasho [114]3 years ago

3 0

Answer:

Yes

Step-by-step explanation:

If they're perpendicular, that means that angle ECM = 90 degrees and angle ACE = 90 degrees. To figure out if this works, plug that into the two equations they give:

ECM = 3x + 15

becomes

90 = 3x + 15

75 = 3x

25 = x

ACE = 4x - 10

becomes

90 = 4x - 10

100 = 4x

25 = x

Since you get x = 25 for both, you know that they are perpendicular because they both measure 90 degrees

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Simplify 4^-4.<br> please help I have 10 minutes

kolezko [41]

Answer:

1/256

Step-by-step explanation:

$4^{-4}$

$(1/4)^{4}$

=> 1/256

7 0

3 years ago

In a simple regression analysis (where y is a dependent and x an independent variable), if the y-intercept is positive, then it

Rom4ik [11]

Answer:

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

Where:

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

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

$\bar x= \frac{\sum x_i}{n}$

$\bar y= \frac{\sum y_i}{n}$

And we can find the intercept using this:

$b=\bar y -m \bar x$

On this case the correct answer would be:

E. none of the above

Since the intercept has no association between the increase/decrease of the dependent variable respect to the independent variable

Step-by-step explanation:

Assuming the following options:

A. there is a positive correlation between X and Y

B. there is a negative correlation between X and Y

C. if X is increased, Y must also increase

D. if Y is increased, X must also increase

E. none of the above

If we want a model $y = mx +b$ where m represent the lope and b the intercept

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

Where:

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

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

$\bar x= \frac{\sum x_i}{n}$

$\bar y= \frac{\sum y_i}{n}$

And we can find the intercept using this:

$b=\bar y -m \bar x$

On this case the correct answer would be:

E. none of the above

Since the intercept has no association between the increase/decrease of the dependent variable respect to the independent variable

3 0

2 years ago

Solve the two step equation 8x+38=60

Paladinen [302]

Answer:

x = 2.75

Step-by-step explanation:

The goal here is to isolate the variable, or to get x by itself. We can do this by using simple math. The first step is to move every thing to the opposite side of x. We do this by subtracting 38 from 60, which leaves us with 22. Now we want divide 22 by 8. After doing this we are left with the equation x = 2.75. I know that at first fractions and decimals seem annoying and they feel like a lot of work. But if you take a second to really look at them, you will realize they are not that bad. As in most cases with math, looks can be deceiving

8 0

3 years ago

The management of a relatively new social networking website named BooglePlus is conducting a pilot study comparing use of its o

zavuch27 [327]

Answer:

0.0623 ± ( 2.056 )( 0.0224 ) can be used to compute a 95% confidence interval for the slope of the population regression line of y on x

Step-by-step explanation:

Given the data in the question;

sample size n = 28

slope of the least squares regression line of y on x or sample estimate = 0.0623

standard error = 0.0224

95% confidence interval

level of significance ∝ = 1 - 95% = 1 - 0.95 = 0.05

degree of freedom df = n - 2 = 28 - 2 = 26

∴ the equation will be;

⇒ sample estimate ± ( t-test) ( standard error )

⇒ sample estimate ± ( $t_{\alpha /2, df$ ) ( standard error )

⇒ sample estimate ± ( $t_{0.05 /2, 26$ ) ( standard error )

⇒ sample estimate ± ( $t_{0.025, 26$ ) ( standard error )

{ from t table; ( $t_{0.025, 26$ ) = 2.055529 = 2.056

so we substitute

⇒ 0.0623 ± ( 2.056 )( 0.0224 )

Therefore, 0.0623 ± ( 2.056 )( 0.0224 ) can be used to compute a 95% confidence interval for the slope of the population regression line of y on x

5 0

3 years ago

You select a marble from two different bags. You have a 30% chance of choosing a blue marble from the first bag and a 70% chance

pogonyaev

Answer:

50 percent is the average

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3 years ago

Need help with some practice questions since all are different types I'm asking alot sorry!​

Need help with some practice questions since all are different types I'm asking alot sorry!