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3 years ago

PLEASEEEEEEEEE HELPPPPPPPP!!!!!!!

Mathematics

2 answers:

ANTONII [103]3 years ago

8 0

Second and 4th are your answers!

Bumek [7]3 years ago

7 0

Answer 2nd and the 4th one
Hope this helps

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There are 8 red marbles and 32 blue marbles in a jar. What is the ratio of red marbles to blue marbles?

andrey2020 [161]

8:32 simplyfies to 1:4 .....there is your answer 1:4

3 0

3 years ago

Read 2 more answers

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

Find the area of the shape shown below.

bija089 [108]

Answer:

i think its 4,800

Step-by-step explanation:

multiply all the sides

5 0

2 years ago

Read 2 more answers

Anyone can find this?

Mademuasel [1]

Answer:

a=34 °

b=76°

c=70°

d=70°

Step-by-step explanation:

The angles 76° , 34°, and c make up a triangle. A triangle has a sum of 180°.

180° = 76° + 34° +c

c=70°

The parallel lines create 2 congruent triangles so we can use the same angles from the first triangle for the second one.

7 0

3 years ago

The area of a circle with radius r is given by A = π r2. Find the area of a circle with radius 7 centimeters. Use 3.14 for π..

scZoUnD [109]

Step-by-step explanation:

Hey there!

Given;

Radius of a circle (r) = 7cm

Now;

We know that;

Area of circle (a) = π*(r^2)

= 3.14*(7^2)

= 3.14*49

= 153.86 cm^2

Therefore, the area of a circle is 153.86 cm^2.

Hope it helps...

4 0

3 years ago