Plz really ned help on this really easy!! simplify: 4(5x + 12) Thank you all in advance!!!

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

A cell phone company has a basic monthly plan of $40 plus $0.45 for any minutes used over 700. Before receiving his statement, J

Serga [27]

Ok so we know he used over 700 because he was charged more than 40. Then we take the $8.10 and divide 0.45 into it. This then gives you 18 more minutes. Then add 18 to 700 and you get 718 min.

4 0

3 years ago

Jose and Maris work for different car dealerships. Jose earns a monthly salary of $3,500 plus a 6% commission on his sales, x. M

aev [14]

Answer: d.3,500 + 0.06x > 4,000 + 0.04x

Step-by-step explanation:

Hi, to answer this question we have to write each inequality:

Jose earns a monthly salary of $3,500 plus a 6% commission on his sales, x.

So, his monthly earnings must be equal to the sum of the fixed monthly salary ($3500) plus the product of the number of sales (x) and the commission percentage in decimal form (divided by 100):

So:

Jose’s earnings: 3,500 + x (6/100)

Jose’s earnings: 3,500 + 0.06x

Maris earns a monthly salary of $4,000 plus a 4% commission on her sales.

So, her monthly earnings must be equal to the sum of the fixed monthly salary ($4000) plus the product of the number of sales (x) and the commission percentage in decimal form (divided by 100):

Maris’ earnings: 4000+ x (4/100)

Maris’ earnings: 4000+ 0.04 x

Since Jose's earnings must be greater than Maris' earnings

3,500 + 0.06x >4000+ 0.04 x

4 0

3 years ago

A group of people want to buy tickets to a baseball game. At least 18 people need to buy tickets in order to get the group rate.

borishaifa [10]

Answer:

a or b

Step-by-step explanation:

it should be p≥18

greater then or equal to 18. because if you have 18, you can get the group rate and I'd you have more than 18 you can also get the group rate.

4 0

3 years ago

Media experts claim that daily print newspapers are declining because of Internet access. Listed below, from left to right and

yKpoI14uk [10]

Answer:

(a) The median is 1478

(b) Null hypothesis H₀ : μ₁ = μ₂

Alternative hypothesis Hₐ : μ₁ > μ₂

(c) The test statistic $t_{\alpha/2}$ is 6.678155

(d) The p value is 1.2×10⁻¹¹

(e) We reject our null hypothesis H₀. In terms of the test, there is sufficient evidence to suggest that there is a trend in the numbers of daily newspaper because the probability for a decrease in the numbers is very high

Step-by-step explanation:

(a) Here we have the data as follows;

1623 1586 1574 1554 1544 1531 1519 1513 1491 1484 1478 1471 1458 1456 1458 1453 1438 1428 1405 1395 1377

The median is = 1478

Therefore we have above the median

1623 1586 1574 1554 1544 1531 1519 1513 1491 1484

The mean, $\bar{x}_{1}$ = 1541.9

Standard deviation, σ₁ = 41.38224257

n₁ = 10

Below the median

1471 1458 1456 1458 1453 1438 1428 1405 1395 1377

The mean, $\bar{x}_{2}}$ = 1433.9

Standard deviation, σ₂ = 30.04812806

n₂ = 10

(b) Null hypothesis H₀ : μ₁ = μ₂

Alternative hypothesis Hₐ : μ₁ > μ₂

(c) The formula for t test is given by;

$t_{\alpha/2} =\frac{(\bar{x}_{1}-\bar{x}_{2})}{\sqrt{\frac{\sigma_{1}^{2} }{n_{1}}-\frac{\sigma _{2}^{2}}{n_{2}}}}$

df = 10 - 1 = 9, α = 0.05

Therefore, the test statistic $t_{\alpha/2}$ = 6.678155

(d) The p value from statistical relations is Probability p = 1.2×10⁻¹¹

Critical z at 5% confidence level = 1.645

Since P << 0.05, e reject the

(e) Therefore, we reject our null hypothesis H₀. In terms of the test, there is sufficient evidence to suggest that there is a trend in the numbers of daily newspaper because the probability for a decrease in the numbers is very high.

5 0

3 years ago