Grade 7 math extra credit

2.2x+4.4 whats the coeffficent and variable

mamaluj [8]

<span>2.2(x+2) would be the answer of the problem </span>

3 0

3 years ago

Which matrix is equal to P + Q?

Afina-wow [57]

Answer:
$\begin{bmatrix}-1.1 & 9.5\\-5.7 & 0.8\\6.1 & 0.7\end{bmatrix}$

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Add up the corresponding elements

Row1,Column1: 6.1+(-7.2) = -1.1
Row1,Column2: 1.9+7.6 = 9.5
Row2,Column1: -7.5+1.8 = -5.7
Row2,Column2: 2.2+(-1.4) = 0.8
Row3,Column1: 3.8+2.3 = 6.1
Row3,Column2: -1.4+2.1 = 0.7

So that's why the answer is
$\begin{bmatrix}-1.1 & 9.5\\-5.7 & 0.8\\6.1 & 0.7\end{bmatrix}$

3 0

3 years ago

A development economist is studying income growth in a rural area of a developing country. The last census of the population of

kykrilka [37]

Answer:

If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL reject the null hypothesis, so we can say that the population mean is not singificantly higher than 425.

Step-by-step explanation:

Data given and notation

$\bar X=433.75$ represent the mean height for the sample

$\sigma=\sqrt{2500}=50$ represent the population standard deviation for the sample

$n=100$ sample size

$\mu_o =425$ represent the value that we want to test

$\alpha=0.01$ represent the significance level for the hypothesis test.

z would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean height actually is higher than the mean height for men in 1960, the system of hypothesis would be:

Null hypothesis: $\mu \leq 425$

Alternative hypothesis: $\mu > 425$

Since we know the population deviation so is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{433.75-425}{\frac{50}{\sqrt{100}}}=1.75$

P-value

Since is a one right tail test the p value would be:

$p_v =P(z>1.75)=1-P(z$

Conclusion

If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL reject the null hypothesis, so we can say that the population mean is not singificantly higher than 425.

3 0

3 years ago

The set of points (-3, 4), (-1, 1), (-3,-2), and (-5,1) identifies the vertices of a quadrilateral. Which is the most specific d

KIM [24]

Answer:

Option (4). Rhombus

Step-by-step explanation:

From the figure attached,

Distance AB = $\sqrt{(x_{2}-x_{1})^2+(y_{2}-y_{1})^2}$