Please help giving brainlest and points!!:) thank you!!

Please I really need help!!! Can someone pls help me??

Tom [10]

A: angle E B: angle P

7 0

3 years ago

Trigonometry is the worst please someone answer this for me ... no links please

quester [9]

Answer: Approximately 22.62 degrees

===============================================

Work Shown:

cos(angle) = adjacent/hypotenuse

cos(y) = 12/13

y = arccos(12/13)

y = 22.6198649

y = 22.62

Notes:

Arccosine is the same as inverse cosine. On your calculator there should be a button labeled $\cos^{-1}$
Make sure your calculator is in degree mode
The decimal result for y, shown above, is approximate. I rounded to two decimal places to show the final answer. Round however you need to if your teacher instructs otherwise.

5 0

3 years ago

A survey sampled men and women workers and asked if they expected to get a raise or promotion this year. Suppose the survey samp

Oksanka [162]

Answer:

a)

The null hypothesis is: $H_0: p_M - p_W = 0$

The alternative hypothesis is: $H_1: p_M - p_W > 0$

b) For men is of 0.49 and for women is of 0.36.

c) The p-value of the test is 0.0039 < 0.01, which means that the results are statistically significant so that you can conclude a greater proportion of men expect to get a raise or a promotion this year.

Step-by-step explanation:

Before solving this question, we need to understand the central limit theorem and subtraction of normal variables.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean $\mu = p$ and standard deviation $s = \sqrt{\frac{p(1-p)}{n}}$

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

Men:

98 out of 200, so:

$p_M = \frac{98}{200} = 0.49$

$s_M = \sqrt{\frac{0.49*0.51}{200}} = 0.0353$

Women:

72 out of 200, so:

$p_W = \frac{72}{200} = 0.36$

$s_W = \sqrt{\frac{0.36*0.64}{200}} = 0.0339$

a. State the hypothesis test in terms of the population proportion of men and the population proportion of women.

At the null hypothesis, we test if the proportion are similar, that is, if the subtraction of the proportions is 0, so:

$H_0: p_M - p_W = 0$

At the alternative hypothesis, we test if the proportion of men is greater, that is, the subtraction is greater than 0, so:

$H_1: p_M - p_W > 0$

b. What is the sample proportion for men? For women?

For men is of 0.49 and for women is of 0.36.

c. Use α= 0.01 level of significance. What is the p-value and what is your conclusion?

From the sample, we have that:

$X = p_M - p_W = 0.49 - 0.36 = 0.13$

$s = \sqrt{s_M^2+s_W^2} = \sqrt{0.0353^2 + 0.0339^2} = 0.0489$

The test statistic is:

$z = \frac{X - \mu}{s}$

In which X is the sample mean, $\mu$ is the value tested at the null hypothesis, and s is the standard error, so:

$z = \frac{0.13 - 0}{0.0489}$

$z = 2.66$

P-value of the test and decision:

The p-value of the test is the probability of finding a difference above 0.13, which is the p-value of z = 2.66.

Looking at the z-table, z = 2.66 has a p-value of 0.9961.

1 - 0.9961 = 0.0039.

The p-value of the test is 0.0039 < 0.01, which means that the results are statistically significant so that you can conclude a greater proportion of men expect to get a raise or a promotion this year.

4 0

3 years ago

A furniture company manufactures desks and chairs. Each desk uses four units of wood, and each chair uses three units of wood. A

Pavlova-9 [17]

Answer:

$180000

Step-by-step explanation:

Let's c be the number of chair and d be the number of desks.

The constraint functions:

- Unit of wood available 4d + 3c <= 2000 or d <= 500 - 0.75c

- Number of chairs being at least twice of desks c >= 2d or d <= 0.5c

c >= 0

d >= 0

The objective function is to maximize the profit function

P (c,d) = 400d + 250c

We draw the 2 constraint functions (500 - 0.75c and 0.5c) on a c-d coordinates (witch c being the horizontal axis and d being the vertical axis) and find the intersection point 0.5c = 500 - 0.75c

1.25c = 500

c = 400 and d = 0.5c = 200 so P(400, 200) = $250*400 + $400*200 = $180,000

The 500 - 0.75c intersect with c-axis at d = 0 and c = 500 / 0.75 = 666 and P(666,0) = 666*250 = $166,500

So based on the available zones in the chart we can conclude that the maximum profit we can get is $180000

7 0

3 years ago

A ceiling fan with 16-in. blades rotates at 45 rpm.

Kobotan [32]

A. We're told the fan completes 45 full revolutions every minute. One full revolution is $2\pi\,\mathrm{rad}$ , so the fan has an angular speed of

$\dfrac{2\pi\,\mathrm{rad}}{1\,\mathrm{rev}}\cdot\dfrac{45\,\mathrm{rev}}{\mathrm{min}}=90\pi\dfrac{\rm{rad}}{\rm{min}}$

B. Throughout one full revolution of the fan, a point at the tip of one of the fan's blades travels the circumference of a circle with radius 16 in. The circumference is then $2\pi(16\,\mathrm{in})=32\pi\,\mathrm{in}$ . This means the linear speed is

$\dfrac{32\pi\,\mathrm{in}}{1\,\mathrm{rev}}\cdot\dfrac{45\,\mathrm{rev}}{\mathrm{min}}=1440\pi\,\dfrac{\rm{in}}{\rm{min}}$

8 0

3 years ago