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3 years ago

HELP WILL PICK BRAINLIEST!

Mathematics

1 answer:

jeka57 [31]3 years ago

8 0

Answer:

The function has no undefined points nor domain constraints, therefore the Domain is (-∞ < x < ∞). Since your answers don't match the real results, the interval notation is (-∞,∞)

Step-by-step explanation:

You might be interested in

A right triangle has side lengths 19 inches, 180 inches, and 181 inches. What is the length of the hypotenuse and why?

IgorC [24]

Answer:

181 is the longest side. the hyp is the longest side of a right triangle.

4 0

3 years ago

Some types of algae have the potential to cause damage to river ecosystems. Suppose the accompanying data on algae colony densit

Phantasy [73]

Answer:

$y=-2.95836 x +234.56159$

Step-by-step explanation:

We assume that th data is this one:

x: 50, 55, 50, 79, 44, 37, 70, 45, 49

y: 152, 48, 22, 35, 43, 171, 13, 185, 25

a) Compute the equation of the least-squares regression line. (Round your numerical values to five decimal places.)For this case we need to calculate the slope with the following formula:

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

Where:

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

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

So we can find the sums like this:

$\sum_{i=1}^n x_i =50+ 55+ 50+ 79+ 44+ 37+ 70+ 45+ 49=479$

$\sum_{i=1}^n y_i =152+ 48+ 22+ 35+ 43+ 171+ 13+ 185+ 25=694$

$\sum_{i=1}^n x^2_i =50^2 + 55^2 + 50^2 + 79^2 + 44^2 + 37^2 + 70^2 + 45^2 + 49^2=26897$

$\sum_{i=1}^n y^2_i =152^2 + 48^2 + 22^2 + 35^2 + 43^2 + 171^2 + 13^2 + 185^2 + 25^2=93226$

$\sum_{i=1}^n x_i y_i =50*152+ 55*48+ 50*22+ 79*35+ 44*43+ 37*171+ 70*13+ 45*185+ 49*25=32784$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=26897-\frac{479^2}{9}=1403.556$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}=32784-\frac{479*694}{9}=-4152.22$

And the slope would be:

$m=-\frac{-4152.222}{1403.556}=-2.95836$

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

$\bar x= \frac{\sum x_i}{n}=\frac{479}{9}=53.222$

$\bar y= \frac{\sum y_i}{n}=\frac{694}{9}=77.111$

And we can find the intercept using this:

$b=\bar y -m \bar x=77.1111111-(-2.95836*53.22222222)=234.56159$

So the line would be given by:

$y=-2.95836 x +234.56159$

7 0

3 years ago

Help me please I NEED to pass this

Alina [70]

OPTION C is the correct answer.

Hope it helps you.

4 0

3 years ago

You are planning a survey of starting salaries for recent computer science majors. In a recent survey by the National Associatio

nydimaria [60]

Answer:

A sample size of 554 is needed.

Step-by-step explanation:

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

$\alpha = \frac{1 - 0.95}{2} = 0.025$

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

That is z with a pvalue of $1 - 0.025 = 0.975$ , so Z = 1.96.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

Standard deviation is known to be $12,000

This means that $\sigma = 12000$

What sample size do you need to have a margin of error equal to $1000, with 95% confidence?

This is n for which M = 1000. So

$M = z\frac{\sigma}{\sqrt{n}}$

$1000 = 1.96\frac{12000}{\sqrt{n}}$

$1000\sqrt{n} = 1.96*12$

Dividing both sides by 1000:

$\sqrt{n} = 1.96*12$

$(\sqrt{n})^2 = (1.96*12)^2$

$n = 553.2$

Rounding up:

A sample size of 554 is needed.

5 0

3 years ago

Round 223 to the nearest 10

zubka84 [21]

220. Think of it this way: 5 and above, give it a shove, 4 and below, keep it down low. That means that if the last number is five or above, push it up to the nearest 10, and if the last number is four or below, round to the lowest 10.

8 0

3 years ago