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2 years ago

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Mathematics

1 answer:

Drupady [299]2 years ago

5 0

Answer: About 830 dollars

Step-by-step explanation: find 15% off on 897 then find 7.5 percent of 897, then add them together.

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Why do the roots of a quadratic equation have the opposite sign of the factors of a quadratic equation? HELPP PLEASE ASAPP

jenyasd209 [6]

Answer: whas the Answer?

Step-by-step explanation:

6 0

3 years ago

1. (5pt) In a recent New York City marathon, 25,221 men finished and 253 dropped out. Also,

gladu [14]

Answer:

(a) Explained below.

(b) The 99% confidence interval for the difference between proportions is (-0.00094, 0.00494).

Step-by-step explanation:

The information provided is:

n (Men who finished the marathon) = 25,221

n (Women who finished the marathon) = 12,883

Compute the proportion of men and women who finished the marathon as follows:

$\hat p_{1}=\frac{25221}{25221 +253}=0.99\\\\\hat p_{2}=\frac{12883 }{12883+163}=0.988$

The combined proportion is:

$\hat P=\frac{X_{1}+X_{2}}{n_{1}+n_{2}}\\\\=\frac{25221+12883}{38520}\\\\=0.989$

(a)

The hypothesis is:

H₀: The rate of those who finish the marathon is the same for men and women, i.e. p₁ - p₂ = 0.

Hₐ: The rate of those who finish the marathon is not same for men and women, i.e. p₁ - p₂ ≠ 0.

Compute the test statistic as follows:

$Z=\frac{\hat p_{1}-\hat p_{2}}{\sqrt{\hat P(1-\hat P)\cdot [\frac{1}{n_{1}}+\frac{1}{n_{2}}]}}$

$=\frac{0.99-0.988}{\sqrt{0.989(1-0.989)\times[\frac{1}{25474}+\frac{1}{13046}]}}\\\\=1.78$

Compute the p-value as follows:

$p-value=2\times P(Z>1.78)\\\\=2\times 0.03754\\\\=0.07508\\\\\approx 0.075$

The p-value of the test is more than the significance level. The null hypothesis was failed to be rejected.

Thus, concluding that the rate of those who finish is the same for men and women.

(b)

Compute the 99% confidence interval for the difference between proportions as follows:

The critical value of z for 99% confidence level is 2.58.

$CI=(\hat p_{1}-\hat p_{2})\pm z_{\alpha/2}\cdot\sqrt{\frac{\hat p_{1}(1-\hat p_{1})}{n_{1}}+\frac{\hat p_{2}(1-\hat p_{2})}{n_{2}}}$

$=(0.99-0.988)\pm 2.58\times\sqrt{\frac{0.99(1-0.99)}{25474}+\frac{0.988(1-0.988)}{13046}}\\\\=0.002\pm 0.00294\\\\=(-0.00094, 0.00494)\\\\$

Thu, the 99% confidence interval for the difference between proportions is (-0.00094, 0.00494).

6 0

3 years ago

Rex has a collection of 160 toy dinosaurs to put into 4 boxes. He puts 5 handfuls of toy dinosaurs in each box. There are no toy

SpyIntel [72]

Answer: 8 dinos

Step-by-step explanation:

there are 4 boxes and 5 handfuls in each. divide 160 by 4 and divide that, 40, by 5 to get 8

8 0

3 years ago

Simplify the expression .

katovenus [111]

$10xy^2(3x^3-5x)-2x^2y(6y^3+3y)=\\\\=30x^4y^2-50x^2y^2-12x^3y^4-6x^2y^2=\\\\=\boxed{30x^4y^2-12x^3y^4-56x^2y^2}$

3 0

3 years ago

Consider a manufacturing process with a quality inspection station. In the past, 10% of parts are defective. As soon as one defe

Kruka [31]

Answer:

0.9

Step-by-step explanation:

10% is equal to 0.1

The probability of having defective parts in a pile of parts is 0.1

Before the process is stopped, 1 part has to be defective.

In a pile of 9 parts, the probability that a part is defective 0.1 of 9, which is = 0.9 hence, approximately one (1) part will be defective in a pile of 9 parts and the process will be stopped.

Since there was no defective part among the first 6 parts, P(d) was 0

That is, probability of a defective part was zero.

7 0

3 years ago