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3 years ago

I need help really bad

Mathematics

1 answer:

Stella [2.4K]3 years ago

5 0

The answer is 18. You add 5 to both sides of the equation. the 5 cancels out. You are left with 2/3x=12. Then you divide 12 by 2/3 to get x. 12 divided by 2/3 is 18

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A simple random sample of items resulted in a sample mean of . The population standard deviation is . a. Compute the confidence

Varvara68 [4.7K]

Answer:

(a): The 95% confidence interval is (46.4, 53.6)

(b): The 95% confidence interval is (47.9, 52.1)

(c): Larger sample gives a smaller margin of error.

Step-by-step explanation:

Given

$n = 30$ -- sample size

$\bar x = 50$ -- sample mean

$\sigma = 10$ --- sample standard deviation

Solving (a): The confidence interval of the population mean

Calculate the standard error

$\sigma_x = \frac{\sigma}{\sqrt n}$

$\sigma_x = \frac{10}{\sqrt {30}}$

$\sigma_x = \frac{10}{5.478}$

$\sigma_x = 1.825$

The 95% confidence interval for the z value is:

$z = 1.960$

Calculate margin of error (E)

$E = z * \sigma_x$

$E = 1.960 * 1.825$

$E = 3.577$

The confidence bound is:

$Lower = \bar x - E$

$Lower = 50 - 3.577$

$Lower = 46.423$

$Lower = 46.4$ --- approximated

$Upper = \bar x + E$

$Upper = 50 + 3.577$

$Upper = 53.577$

$Upper = 53.6$ --- approximated

So, the 95% confidence interval is (46.4, 53.6)

Solving (b): The confidence interval of the population mean if mean = 90

First, calculate the standard error of the mean

$\sigma_x = \frac{\sigma}{\sqrt n}$

$\sigma_x = \frac{10}{\sqrt {90}}$

$\sigma_x = \frac{10}{9.49}$

$\sigma_x = 1.054$

The 95% confidence interval for the z value is:

$z = 1.960$

Calculate margin of error (E)

$E = z * \sigma_x$

$E = 1.960 * 1.054$

$E = 2.06584$

The confidence bound is:

$Lower = \bar x - E$

$Lower = 50 - 2.06584$

$Lower = 47.93416$

$Lower = 47.9$ --- approximated

$Upper = \bar x + E$

$Upper = 50 + 2.06584$

$Upper = 52.06584$

$Upper = 52.1$ --- approximated

So, the 95% confidence interval is (47.9, 52.1)

Solving (c): Effect of larger sample size on margin of error

In (a), we have:

$n = 30$ $E = 3.577$

In (b), we have:

$n = 90$ $E = 2.06584$

Notice that the margin of error decreases when the sample size increases.

4 0

3 years ago

You have $814 that you want to share equally between 5 charities.

kifflom [539]

Answer:

give each charity $60

Step-by-step explanation:

$814 to divide equally to 5 charities.

From 814 if we give -100, -100, -100, -100, -100, we have left 314 to split in 5

the most useful next step is to give each charity $60

From $814 if we give -100, -100, -100, -100, -100

-60, -60, -60, -60, -60

we have left now:

814 -5*100 -5*60 = 814-500-300 = $14 left to split among the 5 charity.

6 0

3 years ago

Whats 18÷19 ok im only in grade 5 so

anastassius [24]

18÷19=0.94736....................

5 0

3 years ago

Read 2 more answers

Use the place value chart to help right 430,697 In expanded form

Dmitry [639]

Answer:

400,000

+ 30,000

+ 0

+ 600

+ 90

+ 7

I am joyous to assist anyone at anytime :)

7 0

3 years ago

Here's another one

Alex73 [517]

Answer:

Supplementary Angles

x = 62

Step-by-step explanation:

Supplementary angles equal 180.

180 - 118 = 62

I hope this helps!

4 0

3 years ago