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2 years ago

13

use the polygon tool to draw an image of the given polygon under a dilation with a scale factor of 1/3 and center of dilation at

0 0

1 answer:

Sveta_85 [38]2 years ago

5 0

Answer:

x-y and AxR

Step-by-step explanation:

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A researcher gathers data on the length of essays (number of lines) and the SAT scores received for a sample of students enrol

LenaWriter [7]

Answer:

(C) The slope of the regression equation is not significantly different from zero

Step-by-step explanation:

Let's suppose that we have the following linear model:

$y= \beta_o +\beta_1 X$

Where Y is the dependent variable and X the independent variable. $\beta_0$ represent the intercept and $\beta_1$ the slope.

In order to estimate the coefficients $\beta_0 ,\beta_1$ we can use least squares estimation.

If we are interested in analyze if we have a significant relationship between the dependent and the independent variable we can use the following system of hypothesis:

Null Hypothesis: $\beta_1 = 0$

Alternative hypothesis: $\beta_1 \neq 0$

Or in other wouds we want to check is our slope is significant.

In order to conduct this test we are assuming the following conditions:

a) We have linear relationship between Y and X

b) We have the same probability distribution for the variable Y with the same deviation for each value of the independent variable

c) We assume that the Y values are independent and the distribution of Y is normal

The significance level is provided and on this case is $\alpha=0.05$

The standard error for the slope is given by this formula:

$SE_{\beta_1}=\frac{\sqrt{\frac{\sum (y_i -\hat y_i)^2}{n-2}}}{\sqrt{\sum (X_i -\bar X)^2}}$

Th degrees of freedom for a linear regression is given by $df=n-2$ since we need to estimate the value for the slope and the intercept.

In order to test the hypothesis the statistic is given by:

$t=\frac{\hat \beta_1}{SE_{\beta_1}}$

The confidence interval for the slope would be given by this formula:

$\hat \beta_1 + t_{n-2, \alpha/2} \frac{\sqrt{\frac{\sum (y_i -\hat y_i)^2}{n-2}}}{\sqrt{\sum (X_i -\bar X)^2}}$

And using the last formula we got that the confidence interval for the slope coefficient is given by:

$-0.88 < \beta_1$

IF we analyze the confidence interval contains the value 0. So we can conclude that we don't have a significant effect of the slope on this case at 5% of significance. And the best option would be:

(C) The slope of the regression equation is not significantly different from zero

6 0

2 years ago

Your tutor asks you to record the time you spend using IT during the week. You have recorded this time below: Day Time Monday 0.

NikAS [45]

Let us convert all figures into decimals so that we can compare them easily.

Monday 0.3

Tuesday 15% = 0.15

Wednesday 1/6 = 0.1666

Thursday 0.2

Friday 1/8 = 0.125

Clearly, I spent the least amount of time on Friday using IT and the time is 0.125 or 1/8.

7 0

2 years ago

Basic math equations and calculations play an important role in many jobs tasks. If you were working at a grocery store and your

OverLord2011 [107]

Given :

Price of cereal without off, C = $2.88 .

Percentage off, P = 20% .

To Find :

Price after applying 20% off.

Solution :

Final price = Initial price - 20 % of initial price

$F = 2.88 - 2.88\times \dfrac{20}{100}\\\\F=2.88-0.576\\\\F=\$ 2.304$

Therefore, final price after sale is $2.304 .

Hence, this is the required solution.

8 0

2 years ago

Let X represent the amount of time until the next student will arrive in the library parking lot at the university. If we know t

Ber [7]

Answer:

The probability that it will take more than 10 minutes for the next student to arrive at the library parking lot is 0.0821.

Step-by-step explanation:

The random variable <em>X</em> is defined as the amount of time until the next student will arrive in the library parking lot at the university.

The random variable <em>X</em> follows an Exponential distribution with mean, <em>μ</em> = 4 minutes.

The probability density function of <em>X</em> is:

$f_{X}(x)=\lambda e^{\lambda x};\ x\geq 0, \lambda >0$

The parameter of the exponential distribution is:

$\lambda=\frac{1}{\mu}=\frac{1}{4}=0.25$

Compute the value of P (X > 10) as follows:

$P(X>10)=\int\limits^{\infty}_{10}{0.25e^{-0.25x}}\, dx$

$=0.25\times \int\limits^{\infty}_{10}{e^{-0.25x}}\, dx\\=0.25\times |\frac{e^{0.25x}}{-0.25}|^{\infty}_{10}\\=(e^{-0.25\times \infty})-(e^{-0.25\times 10})\\=0.0821$

Thus, the probability that it will take more than 10 minutes for the next student to arrive at the library parking lot is 0.0821.

3 0

2 years ago

25xy=225 convert to polar form

bixtya [17]

$\bf x=rcos(\theta)\qquad \qquad y=rsin(\theta)\\\\
-----------------------------\\\\
25xy=225\implies xy=\cfrac{225}{25}\implies xy=9
\\\\\\
rcos(\theta)\cdot rsin(\theta)=9\impliedby \textit{common factor}
\\\\\\
r[cos(\theta)sin(\theta)]=9\implies r=\cfrac{9}{cos(\theta)sin(\theta)}$

6 0

2 years ago