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3 years ago

What is the value of x in the following equation? 4(x-1) = 2(x +1)

1 answer:

3 0

Start by multiplying to get rid of parentheses. Then use addition/subtraction to isolate x on one side of the equation. Finally, use division to determine the value of x.

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A professor wants to know how undergraduate students at X University feel about food services on campus, in general. She obtains

hammer [34]

Answer:

15000

Step-by-step explanation:

Given that a professor wants to know how undergraduate students at X University feel about food services on campus, in general. She obtains a list of email addresses of all 15,000 registered undergraduates from the registrar’s office and mails a questionnaire to 300 students selected at random.

Only 150 questionnaires are returned.

So the sample size changed to 150. But population is the number of registered undergraduates which do not change.

Population size = 15000

8 0

3 years ago

Assume you have noted the following prices for books and the number of pages that each book contains. Book Pages (x) Price (y) A

belka [17]

Answer:

a) $y=0.00991 x +1.042$

b) $r^2 = 0.7503^2 = 0.563$

c) $r=\frac{7(30095)-(4210)(49)}{\sqrt{[7(2595100) -(4210)^2][7(354) -(49)^2]}}=0.7503$

Step-by-step explanation:

Data given

x: 500, 700, 750, 590 , 540, 650, 480

y: 7.00, 7.50 , 9.00, 6.5, 7.50 , 7.0, 4.50

Part a

We want to create a linear model like this :

$y = mx +b$

Wehre

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

And:

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

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

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=2595100-\frac{4210^2}{7}=63085.714$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=30095-\frac{4210*49}{7}=625$

And the slope would be:

$m=\frac{625}{63085.714}=0.00991$

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

$\bar x= \frac{\sum x_i}{n}=\frac{4210}{7}=601.429$

$\bar y= \frac{\sum y_i}{n}=\frac{49}{7}=7$

And we can find the intercept using this:

$b=\bar y -m \bar x=7-(0.00991*601.429)=1.042$

And the line would be:

$y=0.00991 x +1.042$

Part b

The correlation coefficient is given by:

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

For our case we have this:

n=7 $\sum x = 4210, \sum y = 49, \sum xy = 30095, \sum x^2 =2595100, \sum y^2 =354$

$r=\frac{7(30095)-(4210)(49)}{\sqrt{[7(2595100) -(4210)^2][7(354) -(49)^2]}}=0.7503$

The determination coefficient is given by:

$r^2 = 0.7503^2 = 0.563$

Part c

$r=\frac{7(30095)-(4210)(49)}{\sqrt{[7(2595100) -(4210)^2][7(354) -(49)^2]}}=0.7503$

4 0

3 years ago

Estimate 856 + 457 by first rounding each number to the nearest hundred.

Lisa [10]

Answer:

865 = 900

457 = 500

900 + 500 = 1,400

856 + 457 = 1,313

5 0

2 years ago

Read 2 more answers

I NEED HELP ASAP!!!! PLEASE HELP!!!

IRISSAK [1]

Answer:

y= 2x-3 m=2 b= -3

Step-by-step explanation:

we distribute 2(x-2)

y-1 = 2(x-2)

y-1 = 2x-4

then add one to both sides

y-1= 2x -4

+1 +1

since it is negative four and you are adding one it would be -3

y= 2x -3 that is your slope intercept form.

y= mx +b so m=2 and b= -3

6 0

3 years ago

N^2+6n+c<br><br> Find the value of c that completes the square

Anon25 [30]

Answer:

The value of ”c” can by found by this formula: (b/2)^2. In this equation the ”b” is 6. So, (6/3)^2=3^2=9.

The value of “c” that completes the square is 9.

6 0

2 years ago