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2 years ago

Pls help me im goin cray cray

Mathematics

1 answer:

lara31 [8.8K]2 years ago

5 0

Answer:

x ≤ 100

Step-by-step explanation:

You need to get the x on one side by itself. Because the x is being divided by -4, you need to multiply -4 by -25. This way, x will be by itself on the left side, and on the right side, you will get 100 after multiplying -4 x -25. You have to flip the greater than or equal symbol because you are bringing a negative number over the sign to the other side.

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A manufacturer reported a sample mean = 22.0 g and a sample standard deviation = 2.5 g based on a sample of 20 of their products

tester [92]

Answer:

$n=(\frac{1.640(2.5)}{2})^2 =4.2 \approx 5$

So the answer for this case would be n=5 rounded up to the nearest integer

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X=22$ represent the sample mean

$\mu$ population mean (variable of interest)

s=2.5 represent the sample standard deviation

n represent the sample size

ME = 2 represent the margin of error accepted

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (2)

And on this case we have that ME =2 and we are interested in order to find the value of n, if we solve n from equation (2) we got:

$n=(\frac{z_{\alpha/2} s}{ME})^2$ (3)

We can use as estimator for the population deviation the sample deviation $\hat \sigma = s$

The critical value for 90% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.05;0;1)", and we got $z_{\alpha/2}=1.640$ , replacing into formula (3) we got:

$n=(\frac{1.640(2.5)}{2})^2 =4.2 \approx 5$

So the answer for this case would be n=5 rounded up to the nearest integer

6 0

2 years ago

Two integers, a and b have product of -48 what is the greatest possible sum of a and b.

dusya [7]

The factors of 48 are:
1 x 48
2 x 24
3 x 16
4 x 12
6 x 8
and visa versa: 48 x 1 etc.

To make the product negative, one of the factors has to be positive and one has to be negative. To find the greatest sum, make the bigger number the positive factor and the smaller number the negative factor. So, -1 x 48 = -48 and the sum of -1 + 48 = 47 which would be the greatest possible sum.

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3 years ago

Which answer best describes the shape of this distribution?

Licemer1 [7]

Do you go to k-12 I would help but I need the answer too XD

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3 years ago

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Tom received an allowance of $300 for his upcoming trip to Canada. He knows that he will spend $15 each day on food. Which equat

WARRIOR [948]

Answer:

m=15d-300

Step-by-step explanation:

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2 years ago

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A piece of pipe is 303/4 inches long. If five pieces, each 41/3 inches long, are cut from the pipe, how many inches of pipe rema

galina1969 [7]

So, what is the total lenght of the pieces that wer cut off?

we multiply the lenght by the number:

4 $\frac{1}{3}$ *5=20+ $\frac{5}{3}$ =21 $\frac{2}{3}$

and we subtract this from the original pipe, that is

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so the correct answer is D!

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