Help me please? i needa help. am bad at maths.

Sam colors each tile in a 4 by 4 grid white or black. A coloring is called rotationally

DiKsa [7]

Answer:

65,280

Step-by-step explanation:

Consider the 4×4 grid ...

$\left[\begin{array}{cc}a&b\\d&c\end{array}\right]$

where each of a, b, c, d is a 2×2 array of tiles. Let's use the notation a' to represent the 2×2 array "a" rotated right 1/4 turn. For 90° rotational symmetry, we must have b=a', c=b'=a'', d=c'=b''=a'''. That is, once "a" is determined, the rest of the grid is determined. Since "a" consists of 4 tiles, each of which can be black or white, there are 2^4 = 16 patterns that have 90° rotational symmetry.

The same will be true of 270° rotational symmetry, for the same reason.

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For 180° rotational symmetry, we must have c=a'' and d=b''. Then the combination of "a" and "b" together fully determines the grid. Together, "a" and "b" consist of 8 tiles, so there are 2^8 = 256 ways to pattern the grid so it will have 180° rotational symmetry. (Of those, 16 have 90° symmetry, and 16 have 270° symmetry. The sets are overlapping.)

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The 16 tiles of the grid can be colored 2^16 = 65,536 different ways. As we have seen, 256 of those colorings result in 180° rotational symmetry. Then the number of colorings that have no rotational symmetry is ...

65,536 -256 = 65,280 . . . . colorings not rotationally symmetric

8 0

3 years ago

the figure above, not drawn to scale, consists of a triangle resting on a square of side 5cm. the height of the triangle is 4cm.

andrezito [222]

Answer:

5x4x2

Step-by-step explanation:

6 0

3 years ago

Brielle is making a mosaic picture that is ¼ foot by ¾ foot. What is the area of her mosaic?

fenix001 [56]

1/4 x 3/4 = 3/16 ft squared

6 0

3 years ago

Test the hypothesis using the P value approach. Be sure the verify the requirements of the test.

Andreas93 [3]

Answer:

$p_v =2*P(z$

If we compare the p value and using the significance level given $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the proportion is not significantly different from 0.77.

Step-by-step explanation:

1) Data given and notation

n=500 represent the random sample taken

X=380 represent the number of people with some characteristic

$\hat p=\frac{380}{500}=0.76$ estimated proportion of adults that said that it is morally wrong to not report all income on tax returns

$p_o=0.76$ is the value that we want to test

$\alpha=0.05$ represent the significance level

Confidence=95% or 0.95

z would represent the statistic (variable of interest)

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

2) Concepts and formulas to use

We need to conduct a hypothesis in order to test the claim that the true proportion is 0.7 .:

Null hypothesis: $p=0.77$

Alternative hypothesis: $p \neq 0.77$

When we conduct a proportion test we need to use the z statistic, and the is given by:

$z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}$ (1)

The One-Sample Proportion Test is used to assess whether a population proportion $\hat p$ is significantly different from a hypothesized value $p_o$ .

<em>Check for the assumptions that he sample must satisfy in order to apply the test </em>

a)The random sample needs to be representative: On this case the problem no mention about it but we can assume it.

b) The sample needs to be large enough

$np_o =500*0.77=385>10$

$n(1-p_o)=384*(1-0.77)=115>10$

3) Calculate the statistic

Since we have all the info requires we can replace in formula (1) like this:

$z=\frac{0.76-0.77}{\sqrt{\frac{0.77(1-0.77)}{500}}}=-0.531$

4) Statistical decision

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.

The significance level provided $\alpha=0.05$ . The next step would be calculate the p value for this test.

Since is a bilateral test the p value would be:

$p_v =2*P(z$

If we compare the p value and using the significance level given $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the proportion is not significantly different from 0.77.

6 0

4 years ago

Given the speeds of each runner below, determine who runs the fastest.

shutvik [7]

Answer:

Adam is the fastest runner

5 0

3 years ago