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3 years ago

Hello me plz I need it.... I really don't understand

Mathematics

1 answer:

Tcecarenko [31]3 years ago

7 0

Answer:

its too blurry and i cant read it

Step-by-step explanation:

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A research firm needs to estimate within 3% the proportion of junior executives leaving large manufacturing companies within thr

Y_Kistochka [10]

Answer:

972 junior executives should be surveyed.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

The margin of error is of:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

35% of junior executives left their company within three years.

This means that $\pi = 0.35$

0.95 = 95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

To update this study, how many junior executives should be surveyed?

Within 3% of the proportion, which means that this is n for which M = 0.03. So

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.03 = 1.96\sqrt{\frac{0.35*0.65}{n}}$

$0.03\sqrt{n} = 1.96\sqrt{0.35*0.65}$

$\sqrt{n} = \frac{1.96\sqrt{0.35*0.65}}{0.03}$

$(\sqrt{n})^2 = (\frac{1.96\sqrt{0.35*0.65}}{0.03})^2$

$n = 971.2$

Rounding up:

972 junior executives should be surveyed.

5 0

3 years ago

In the town zoo 3/28 of the animals are birds of the birds for 4/15 are birds of prey what fraction of the animals at the zoo ar

KIM [24]

4/15 of 3/28....." of " means multiply

4/15 * 3/28 = 12/420 reduces to 1/35 <== birds of prey

7 0

4 years ago

Read 2 more answers

Whoever answer it correctly will get brainliest. :)

r-ruslan [8.4K]

Answer:

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

Which expression is equivalent to (-1.3x - 4.5) -(-2. 1x + 3. 6)?

Reika [66]

Answer:

C) If im wrong im sorry

Step-by-step explanation:

5 0

3 years ago

Work out the area of a semi circle with a radius of 3cm give your answer in terms of pi

Ivenika [448]

<h3>The area of semicircle is $4.5 \pi\ cm^2$ </h3>

Solution:

Given that,

We have to find the area of a semi circle with a radius of 3 cm

The area of semicircle is given as:

$Area\ of\ semicircle = \frac{ \pi r^2}{2}$

Where, r is the radius

From given,

r = 3 cm

Substituting the values we get,

$Area\ of\ semicircle = \frac{ \pi \times 3^2}{2}\\\\Area\ of\ semicircle = \frac{ \pi \times 9}{2}\\\\Area\ of\ semicircle = 4.5 \pi$

Thus the area of semicircle is $4.5 \pi\ cm^2$

4 0

4 years ago