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4 years ago

What is the sum of the polynomials?

Mathematics

1 answer:

lesya [120]4 years ago

5 0

Add the like terms:

8x2+x2=9x2

-9y2-3y2=-12y2

-4x-7x=-11x

Combine each term:

9x2-12y2-11x

Hope this helps!!

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The US Census reported that it takes workers an average of 28 minutes to get home from work with standard deviation 5 minutes. A

xz_007 [3.2K]

Using the z-distribution, as we have the standard deviation for the population, to test the hypothesis, it is found that this is evidence that workers in the large city take longer than 28 minutes to get home from work.

<h3>What are the hypothesis tested?</h3>

At the null hypothesis, it is tested if the mean time is of 28 minutes, that is:

$H_0: \mu = 28$

At the alternative hypothesis, it is tested if the mean time is greater than 28 minutes, that is:

$H_1: \mu > 28$ .

<h3>What is the test statistic?</h3>

The test statistic is given by:

$z = \frac{\overline{x} - \mu}{\frac{\sigma}{\sqrt{n}}}$

The parameters are:

$\overline{x}$ is the sample mean.

$\mu$ is the value tested at the null hypothesis.

$\sigma$ is the standard deviation of the sample.

n is the sample size.

In this problem, the values of the parameters are given by:

$\overline{x} = 32, \mu = 28, \sigma = 5, n = 10$

Hence:

$z = \frac{\overline{x} - \mu}{\frac{\sigma}{\sqrt{n}}}$

$z = \frac{32 - 28}{\frac{5}{\sqrt{10}}}$

$z = 2.53$

<h3>What is the decision?</h3>

Considering that we have a <em>right-tailed test</em>, as we are testing if the mean is greater than a value, with a standard <em>significance level of 0.05</em>, the critical value is of $z^\ast = 1.645$ .

Since the test statistic is greater than the critical value, it is found that this is evidence that workers in the large city take longer than 28 minutes to get home from work.

To learn more about the z-distribution, you can check brainly.com/question/26454209

4 0

2 years ago

Gabriel has a stack of nickels that is 0.72 inch tall. The thickness of a nickel is 0.08 inch. How many nickels does Gabriel hav

olganol [36]

Gabriela has a stack of 9 nickels.
0.72 x 9 = 0.08

7 0

3 years ago

If your lawnmower uses 1/3 of a gallon of gas to cut grass for one hour and you have 5/6 gallins of gas how long can you cut the

Eddi Din [679]

Answer:

Answer is 2 hours

Step-by-step explanation:

You have to change 1/3 to 2/6

5÷2=2.5

8 0

3 years ago

Assume that blood pressure readings are normally distributed with a mean of 124 and a standard deviation of 6.4. If 64 people ar

Murrr4er [49]

Answer:

99.38%

Step-by-step explanation:

We have that the mean (m) is equal to 124, the standard deviation (sd) 6.4 and the sample size (n) = 64

They ask us for P (x <126)

For this, the first thing is to calculate z, which is given by the following equation:

z = (x - m) / (sd / (n ^ 1/2))

We have all these values, replacing we have:

z = (126 - 124) / (6.4 / (64 ^ 1/2))

z = 2.5

With the normal distribution table (attached), we have that at that value, the probability is:

P (z <2.5) = 0.9938

The probability is 99.38%

4 0

3 years ago

( look at picture ) ANSWER ALL CORRECTLY FOR BRAINLIEST! NO EXPLANATION NEEDED <3

just olya [345]

Answer:

Check SbS explanation for all

Step-by-step explanation:

1 = 120

2 = 65

3 = I can't read the no. given, but it would be 180 - (number given)

4 = 34.5

5 = 35

7 0

3 years ago