Can somebody help me? Please..

Which equation represents a parabola that has a focus of (0, 0) and a directrix of y=−6 ? x² = 12y x2=12(y+3) x2=−3(y+3) x2=−3y

Svetlanka [38]

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3 0

3 years ago

Read 2 more answers

You want to obtain a sample to estimate a population proportion. At this point in time, you have no reasonable estimate for the

Vesna [10]

Answer:

A sample size of at least 1,353,733 is required.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of , 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 .

The margin of error is:

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

98% confidence level

So $\alpha = 0.02$ , z is the value of Z that has a pvalue of $1 - \frac{0.02}{2} = 0.99$ , so $Z = 2.327$ .

You would like to be 98% confident that you esimate is within 0.1% of the true population proportion. How large of a sample size is required?

We need a sample size of at least n.

n is found when M = 0.001.

Since we don't have an estimate for the proportion, we use the worst case scenario, that is $\pi = 0.5$

So

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

$0.001 = 2.327\sqrt{\frac{0.5*0.5}{n}}$

$0.001\sqrt{n} = 2.327*0.5$

$\sqrt{n} = \frac{2.327*0.5}{0.001}$

$(\sqrt{n})^{2} = (\frac{2.327*0.5}{0.001})^{2}$

$n = 1353732.25$

Rounding up

A sample size of at least 1,353,733 is required.

5 0

4 years ago

Troy’s favorite ice cream has 540 calories per serving. If 5/8 of the calories come from fat how many calories come from fat?

dmitriy555 [2]

337.5. multiply 5/8 and 540.

8 0

3 years ago

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How to find the inter quartile range of these 1,1,1,2,2,3,3,4,5

Anna007 [38]

Answer:

2.5

Step-by-step explanation:

1st Quartile (Q1): 1

2nd Quartile (Q2): 2

3rd Quartile (Q3): 3.5

IQR = Q3 - Q1 = 3.5 - 1 = 2.5

5 0

3 years ago

PLEASE HELP‼️‼️Drag the expression that is the most reasonable measurement for each object.

Afina-wow [57]

Answer:

A. Length of a Tour Bus ↔ #2. 1.1 × 10¹ meters

B. Width of an apple ↔ #3. 4 × 10⁰ centimeters

C. Distance from Earth to a Satellite ↔ #6. 8 × 10² kilometers

D. Thickness of a human hair ↔ #5. 9 × 10¹ micrometers

Explanation:

A. Length of a tour bus.

The length of a tour bus should be measured in meters. It sure is way less than 1 kilometer and way more than a few centimeters. It could be about some meters, more than 5 meters, may be between 10 meters and 15 meters.

The measurement in the box # 2. is 1.1 × 10¹ meters, which is equivalent to 1.1 × 10meters = 11 meters. Thus, this is a reasonable length.

B. Width of an apple.

The most appropiate unit to measure the width of an apple should be centimer. It certanly is shorter than 1 meter and bigger than 1 mm.

The width of an apple could be, more or less, around 8 centimeters. The only measurement in the boxes that is in that order is that in the box #3., 4 × 10⁰ centimeters, because 10⁰ = 1, so 4 × 10⁰ = 4 × 1 = 4centimeters.

C. Distance from Earth to a Satellite

The distance from Earth to a satellite should be measured in kilometers.

You can find in the internet that the distances of the satellites are between 700 kilometers and 36,000 kilometers.

The number in the box #1 is too big, in the order of ten trillions of kilometers, because one trillion is 10¹²; thus that is notreasonalbe (too big).

The number in the box #6 is 8 × 10² kilometers, which is equal to 8 × 100 = 800 kilometers.

Thus, 8 × 10² kilometers (box #6) is the most reasonable measurement for the distance from Earth to a Satellite

D. Thickness of a human hair

Of course, kilometers, meters, centimeters and even milimeters are units too big to measure the thickness of a human hair.

One micrometer is 10⁻⁶ meters or 10⁻³ milimeters.

In the internet you can find that diameter of the humar hairis in the range from 17 micrometers to 181 micrometers.

The measurement in the box #5. is 9 × 10¹ micrometers, which is equivalent to 9 × 10 = 90 micrometers.

Thus, 9 × 10¹ micrometers is the most reasonable measurement fot the thickness of a human hair.

7 0

3 years ago