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3 years ago

7

christian and steven are learning how to ski. Justin falls down every 30 feet. mike falls down every 25 feet. if they both start

skiing from the same point, how far is the first point where they will both fall down?

1 answer:

kondaur [170]3 years ago

3 0

Answer:

150

Step-by-step explanation:

find lcm

30:30 60 90 120 150

25:25 50 75 100 125 150

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9. Which of these was an example of US industrial mobilization for war? (5.1.B) A. Increased factory production of tanks and pla

blagie [28]

Answer:

A

Step-by-step explanation:

Tanks are the Backbone of the Military, they are needed to destroy the Axis Powers during WW2, they also used Captured Enemy Tanks for studying and Produce New Tanks to Counter them.

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3 years ago

Suppose that a researcher is designing a survey to estimate the proportion of adults in your state who oppose a proposed law tha

irinina [24]

Answer:

$n=\frac{0.5 (1-0.5)}{(\frac{0.02}{1.96})^2}= 2401$

So without prior estimation for the population proportion, using a confidence level of 95% if we want a margin of error about 2% we need al least a sample size of 2401.

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".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

Solution to the problem

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

If solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

The margin of error desired for this case is $ME= \pm 0.02$ equivalent to 2% points

For this case we need to assume a confidence level, let's assume 95%. And since we don't have prior estimation for the population proportion of interest the best value to do an approximation is $\hat p =0.5$

In order to find the critical value we need to take in count that we are finding the margin of error for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=\pm 1.96$

Now we have all the values needed and if we replace into equation (b) we got:

$n=\frac{0.5 (1-0.5)}{(\frac{0.02}{1.96})^2}= 2401$

So without prior estimation for the population proportion, using a confidence level of 95% if we want a margin of error about 2% we need al least a sample size of 2401.

5 0

3 years ago

Can someone help please!!!!

Nuetrik [128]

66

Step-by-step explanation:

pretty sure it's 66 because the two lengths added together is 66

7 0

3 years ago

Can someone please help me figure out how to do this problem. We have tried several different ways and none of them come up as b

Ilya [14]

Answer:

74

Step-by-step explanation:

Order of operations: PEMDAS (parentheses, exponents, multiplication, division, addition, subtraction)

5(9)+2(6) ÷ 3 + $5^{2}$

= 45+12÷ 3 +25

=45+4+25

=74

8 0

3 years ago

Read 2 more answers

Annie made fruit punch for 12 people the punch contains sparkling water and 2/3 pint of fruit juice per person if there are 10 2

Furkat [3]

11 pints I believe. Good luck

7 0

3 years ago