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Svetradugi [14.3K]
3 years ago
5

Help This step works because of the ______

Mathematics
2 answers:
lisov135 [29]3 years ago
5 0
I think it's 'b'. Sorry if I'm incorrect. ^^;
solong [7]3 years ago
5 0
This works because of the addition property of equality
a=16--->a+3=16+3
reverse engineering
a+3=16+3--->a=16
now given that 5x-4y=-30
and given also the equation 3x+4y=38
by the addition property
3x+4y+(-30)=38+(-30)
since -30=5x-4y by substituting
3x+4y+(5x-4y)=38-30
which yields
8x=8
the addition property of equality which is B.
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Many elementary school students in a school district currently have ear infections. A random sample of children in two different
Marta_Voda [28]

Answer:

Step-by-step explanation:

The summary of the given data includes;

sample size for the first school n_1 = 42

sample size for the second school n_2  = 34

so 16 out of 42 i.e x_1 = 16 and 18 out of 34 i.e x_2 = 18 have ear infection.

the proportion of students with ear infection Is as follows:

\hat p_1 = \dfrac{16}{42} = 0.38095

\hat p_2 = \dfrac{18}{34}  =  0.5294

Since this is a two tailed test , the null and the alternative hypothesis can be computed as :

H_0 :p_1 -p_2 = 0 \\ \\ H_1 : p_1 - p_2 \neq 0

level of significance ∝ = 0.05,

Using the table of standard normal distribution, the value of z that corresponds to the two-tailed probability 0.05 is 1.96. Thus, we will reject the null hypothesis if the value of the test statistics is less than -1.96 or more than 1.96.

The test statistics for the difference in proportion can be achieved by using a pooled sample proportion.

\bar p = \dfrac{x_1 +x_2}{n_1 +n_2}

\bar p = \dfrac{16 +18}{42 +34}

\bar p = \dfrac{34}{76}

\bar p = 0.447368

\bar p + \bar  q = 1 \\ \\ \bar q = 1 -\bar  p \\  \\\bar q = 1 - 0.447368 \\ \\\bar q = 0.552632

The pooled standard error can be computed by using the formula:

S.E = \sqrt{ \dfrac{ \bar p \bar q}{ n_1} +  \dfrac{\bar p \bar p}{n_2} }

S.E = \sqrt{ \dfrac{  0.447368 *  0.552632}{ 42} +  \dfrac{ 0.447368 *  0.447368}{34} }

S.E = \sqrt{ \dfrac{  0.2472298726}{ 42} +  \dfrac{ 0.2001381274}{34} }

S.E = \sqrt{ 0.01177284105}

S.E = 0.1085

The test statistics is ;

z = \dfrac{\hat p_1 - \hat p_2}{S.E}

z = \dfrac{0.38095- 0.5294}{0.1085}

z = \dfrac{-0.14845}{0.1085}

z = - 1.368

Decision Rule: Since the test statistics is greater than the rejection region - 1.96 , we fail to reject the null hypothesis.

Conclusion: There is insufficient evidence to support the claim that a difference exists between the proportions of students who have ear infections at the two schools

5 0
3 years ago
How to write in inqvality
Kitty [74]

Answer:

If you mean "How do I write an inequality?", the answer is COEFFICIENTxVARIABLE {any symbol} COEFFICIENTxVARIABLE >/< INTEGER

In other words, you should have something like this: -3x + 4v < 63

Or this: 51x - 16v > 11

Or anything along those lines.

8 0
3 years ago
A candidate took a phone poll of 110 people. Of the 110 people polled, 87 said they would vote for the other person. There are 9
SSSSS [86.1K]

Option B

7569 number of people are going to vote for the other candidate

<em><u>Solution:</u></em>

Given that candidate took a phone poll of 110 people

Of the 110 people polled, 87 said they would vote for the other person

There are 9570 people in the district

You can set up this problem like a proportion

Let "x" be the number of people who would vote for the other candidate

\frac{87}{110} = \frac{x}{9570}

To solve proportions, you cross-multiply. This means you multiply the numerator by the other denominator, and the denominator by the other numerator

87 \times 9570 = 110 \times x

832590 = 110x

x = 7569

Thus 7569 number of people are going to vote for the other candidate

6 0
3 years ago
Read 2 more answers
A clothing pattern calls for 4.81 yd2 of fabric. How many square inches of fabric does the pattern use?
Vera_Pavlovna [14]
Total square inches of fabric. 
To answer this question you need to know how many square inches makes up one square yard.

1296 square inches makes one square yard. 

Therefore total square inches =
1296x4.81= 6233.76 square inches
4 0
3 years ago
Read 2 more answers
How do I solve this 4/5 -3/9 I solve
Oksana_A [137]

Answer:

21/45

Step-by-step explanation:

You make the denominator the same and u also multiply the top too and u subtract and thats how u get the answer

3 0
3 years ago
Read 2 more answers
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