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4 years ago

9

The computed chi-square value is positive because the difference between the observed and expected frequencies is _____________.

Select one: a. Squared b. Linear c. Uniform d. Always positive

1 answer:

almond37 [142]4 years ago

3 0

The computed chi-square value is positive because the difference between the observed and expected frequencies is squared.

The formula for chi-square is the sum for all values of (observed - expected)^2 / expected.

Hope this helps!! :)

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Division of fractions

Verizon [17]

Answer:

The first step to dividing fractions is to find the reciprocal (reverse the numerator and denominator) of the second fraction. Next, multiply the two numerators. Then, multiply the two denominators. Finally, simplify the fractions if needed.

5 0

3 years ago

Read 2 more answers

Approximately 2125 heart transplants were performed in a country in 2001. In 2006, the number of heart transplants in the count

professor190 [17]

Answer:

(2001, 2125), (2006, 2360)

Step-by-step explanation:

An ordered pair refers to a pair of numbers or items in a simple and orderly manner. The order in which the items are grouped is very important. In graphs an ordered pair could be the coordinates of various points on the graph in terms of x and y, that is x and y coordinate (x,y).

From the question we are to form two ordered pair in the form (year, number of heart transplants).

to do this we simply fill out the items with their corresponding numbers where the first item is the year and second is the number of heart transplants.

in year 2001 we have (2001, 2125)

in year 2006 we have (2006, 2360)

3 0

3 years ago

Find the minimum and maximum values of the function subject to the given constraint. (if an answer does not exist, enter dne.) f

nata0808 [166]

Via Lagrange multipliers:

$L(x,y,\lambd)=x^2y+x+y+\lambda(xy-5)$
$L_x=2xy+1+\lambda y=0$
$L_y=x^2+1+\lambda x=0$
$L_\lambda=xy-5=0$

$\underbrace{10}_{2xy}+1+\lambda y=0\implies \lambda=-\dfrac{11}y$
$xy=5\implies y=\dfrac5x\implies\lambda=-\dfrac{11}5x$

$\impliesx^2+1+\left(-\dfrac{11}5x\right)x=0\implies x^2=\dfrac56\implies x=\pm\sqrt{\dfrac56}$
$xy=5\implies y=\pm\sqrt{30}$

At these points, we get local minima of $f\left(\pm\sqrt{\dfrac56},\pm\sqrt{30}\right)=\pm2\sqrt{30}$ .

- - -

Another way to do this is to make $f(x,y)$ a function independent of $y$ , which is made possible by the constraint.

$xy=5\implies y=\dfrac5x$
$\implies f(x,y)=f\left(x,\dfrac5x\right)=F(x)=6x+\dfrac5x$
$\implies F'(x)=6-\dfrac5{x^2}=0\implies x=\pm\sqrt{\dfrac56}$

and so on.

8 0

4 years ago

Solve the following equations by factorisation method.Only factorisation not dharacharya.

Luba_88 [7]

Hello, please consider the following.

When $x_1$ and $x_2$ are two roots, we can factorise as

$ax^2+bx+c=a(x-x_1)(x-x_2)=a(x^2-(x_1+x_2)x+x_1x_2)=0$

So for the first equation, we can say that the sum of the zeros is

$\dfrac{a^2+b^2}{2}=\dfrac{a^2}{2}+\dfrac{b^2}{2}$

and the product is

$\dfrac{a^2b^2}{4}=\dfrac{a^2}{2}\dfrac{b^2}{2}$

So we can factorise as below.

$4x^2-2(a^2+b^2)x+a^2b^2=(2x-a^2)(2x-b^2)=0$

And the solutions are

$\boxed{\sf \n\bf \ \dfrac{a^2}{2} \ \ and \ \ \dfrac{b^2}{2}}$

For the second equation, we will complete the square and put the constant on the right side and take the root.

Let's do it!

$9x^2-9(a+b)x+2a^2+5ab+2b^2=0\\\\9(x-\dfrac{a+b}{2})^2-9\dfrac{(a+b)^2}{4}+2a^2+5ab+2b^2=0\\\\9(x-\dfrac{a+b}{2})^2=\dfrac{9(a+b)^2-8a^2-20ab-8b^2}{4}\\\\9(x-\dfrac{a+b}{2})^2=\dfrac{9a^2+18ab+9b^2-8a^2-20ab-8b^2}{4}\\\\9(x-\dfrac{a+b}{2})^2=\dfrac{a^2+b^2-2ab}{4}=\dfrac{(a-b)^2}{4}\\\\(x-\dfrac{a+b}{2})^2=\dfrac{(a-b)^2}{2^2\cdot 3^2}$

We take the root, and we find the two solutions

$\begin{aligned}x_1&=\dfrac{a+b}{2}-\dfrac{a-b}{6}\\\\&=\dfrac{3a+3b-a+b}{6}\\\\&=\dfrac{2a+4b}{6}\\\\&\boxed{=\dfrac{a+2b}{3}}\end{aligned}$

$\begin{aligned}x_1&=\dfrac{a+b}{2}+\dfrac{a-b}{6}\\\\&=\dfrac{3a+3b+a-b}{6}\\\\&=\dfrac{4a+2b}{6}\\\\&\boxed{=\dfrac{2a+b}{3}}\end{aligned}$

Thank you.

6 0

3 years ago

What is 4 and3/4 × 4 and 1/8

Ber [7]

So,

Convert to improper fractions.

$4 \frac{3}{4} --\ \textgreater \ \frac{19}{4}$

$4 \frac{1}{8} --\ \textgreater \ \frac{33}{8}$

Multiply.

$\frac{19}{4}* \frac{33}{8} = \frac{627}{32}\ or\ 19 \frac{19}{32}$

8 0

4 years ago