All categories

3 years ago

For simple linear regression, y = β0 + β1x + u, which one of the following statements is true?

Mathematics

1 answer:

RSB [31]3 years ago

6 0

Answer:

Option a) u is called the "error term". It is the error we make in prediction

Option d) x is called the independent variable because x is independent from y and u.

Step-by-step explanation:

We are given the following information in the question:

$y = \beta_0 + \beta_1x + u$

where y is the dependent variable, x is the independent variable.

$\beta_0$ : It is the value of y when x is zero, that is y-intercept.

$\beta_1$ : It is the coefficient of x in predicting the dependent variable y.

u is the error term.

An error term represents the margin of error.
It refers to the sum of the deviations within the regression line, that is the difference between the predicted value and the observed value of y.

Thus, Option A) u is the error term and Option D) x is called the independent variable because x is independent from y and u are the correct answer.

You might be interested in

25% of x is 30<br><br>x=? <br>please help!!!

Nesterboy [21]

25% of 30 can be found by converting 25% to a decimal and multiplying it by 30.

25% = 0.25

30x0.25=7.5

So x is 7.5.

---

hope it helps

6 0

3 years ago

Find the standard form of the equation of the parabola with a focus at (-2, 0) and a directrix at x = 2.

Leokris [45]

Standard form is, hold a sec

x=2 is directix
that means it opens left or right
so we must use
(y-k)²=4p(x-h)
where vertex is (h,k) and p is distance from focus to vertex
also shortest distance from vertex to directix
the shortest distance from focus to directix is 2p
if p>0 then the parabola opens right
if p<0 then pareabola opens left

so
(-2,0) and x=2
the distance is 4
4/2=2
p=2
wait, positive or negative
focus is to the left of the directix so p is negative
p=-2

vertex is 2 to the right of the focus and 2 to the left of directix
vertex is (0,0)

so
(y-0)²=4(-2)(x-0) or
y²=-8x is da equation
not sure what form is standard tho

4 0

3 years ago

sarah can complete a project in 90 minutes and her sister betty can complete it in 120 minutes if they both work on the project

alukav5142 [94]

Answer:

It will take them approximately 51.43 minutes to complete the project together

Step-by-step explanation:

This is what is called a "shared job" problem.

The best way to work on them is to start by finding the "portion" of the job done by each of the people in the unit of time.

So, for example, Sarah completes the project in 90 minutes, so in the unit of time (that is 1 minute) she completed 1/90 of the total project

Betty completes the project in 120 minutes, so in the unit of time (1 minute) she completes 1/120 of the total project.

We don't know how long it would take for them to complete the project when working together, so we call that time "x" (our unknown).

Now, when they work together completing the entire job in x minutes, in the unit of time they would have done 1/x of the total project.

In the unite of time, the fraction of the job done together (1/x) should equal the fraction of the job done by Sarah (1/90) plus the fraction of the job done by Betty. This in mathematical form becomes:

$\frac{1}{x} =\frac{1}{90} +\frac{1}{120}\\\frac{1}{x} =\frac{4}{360} +\frac{3}{360}\\\frac{1}{x} =\frac{7}{360} \\x=\frac{360}{7} \\x=51.43\,\,min$

So it will take them approximately 51.43 minutes to complete the project together.

8 0

3 years ago

(7.8×10^7) + (9.9×10^7)

Hatshy [7]

(7.8×10⁷)+(9.9×10⁷)
(7.8×10000000)+(9.9×10000000)
(78000000)+(99000000)
177000000

8 0

3 years ago

Andrew

PilotLPTM [1.2K]

Let's say Bailey takes "b" days to paint it.

and Andrew takes "a" days to paint the same house.

now, Andrew is 6 times faster than Bailey, therefore, if Andrew takes "a" days to do it, Bailey takes then "6a" days, or b = 6a.

now, the year they worked together, they finished it in 7 days.

so, after 1 day then, they have only done 1/7 of the whole work.

and Andrew for one day, has done 1/a of the house, whilst Bailey has done 1/b of the house or 1/(6a).

$\bf \stackrel{\textit{Andrew's rate}}{\cfrac{1}{a}}+\stackrel{\textit{Bailey's rate}}{\cfrac{1}{b}}=\stackrel{\textit{1 day of work}}{\cfrac{1}{7}}
\\\\\\
\cfrac{1}{a}+\cfrac{1}{6a}=\cfrac{1}{7}\impliedby 
\begin{array}{llll}
\textit{let's multiply all by }\stackrel{LCD}{42a}\textit{ to toss the}\\
denominators
\end{array}$

$\bf 42a\left( \cfrac{1}{a}+\cfrac{1}{6a} \right)=42a\left( \cfrac{1}{7} \right)\implies 42+7=6a\implies \cfrac{49}{6}=a
\\\\\\
\stackrel{days}{8\frac{1}{6}}=a
\\\\\\
\textit{how many days will it take Bailey then?}\quad b=6a
\\\\\\
b=6\cdot \cfrac{49}{6}\implies b=\stackrel{days}{49}$

6 0

3 years ago