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tamaranim1 [39]

3 years ago

13

I NEED HELP ASAP IM DOING IT NOW. !!!!!!!!!!!!!!!!!!!!!!! Lily likes to collect records. Last year she had 12 records in her col

lection. Now she has 15 records. What is the percent increase of her collection?

2 answers:

ratelena [41]3 years ago

7 0

Answer:

12/10 =1.2 - 1 = 0.2 x 100 = 20%

Step-by-step explanation:

Aleksandr-060686 [28]3 years ago

4 0

Answer:

45% increased.

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△DNS∼△ARH .

nasty-shy [4]

Answer:

i sry i need points

Step-by-step explanation:

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3 years ago

How many unique triangles can be formed with two side lengths of 10 centimeters and one 40° angle?

r-ruslan [8.4K]

Answer:

Two unique triangles possible

Step-by-step explanation:

Given two sides of 10 cm and one 40° angle

<u>If we use these, we'll get isosceles triangle with:</u>

1. Included 40° angle.

<u>Then the other angles will be same and measure:</u>

(180° - 40°)/2 = 70°

2. Adjacent 40° angle. Then one of the angles must be 40° angle as opposite of 10 cm sides.

<u>The remaining angle will measure:</u>

180° - 2*40° = 100°

There no more unique triangles possible, so the answer is two.

3 0

2 years ago

To get ready for snack time, Joseph is putting together dishes of yogurt with fruit in them. He has five cups of strawberries. H

I am Lyosha [343]

Answer:

20 dishes

Step-by-step explanation:

<u>Divide the total number of cups by the number required for each dish:</u>

5 : 1/4 =
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5 0

2 years ago

Read 2 more answers

The following list shows the colours of a random selection of sweets.

Westkost [7]

Answer:

Categorical or Continuous.

Step-by-step explanation:

Because the red appears in each colours (continuous)

6 0

2 years ago

Nitrates are groundwater contaminants derived from fertilizer, septic tank seepage and other sewage. Nitrate poisoning is partic

o-na [289]

Answer:

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

And rounded up we have that n=2401

b) $n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

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".

Solution to the problem

In order to find the critical value we need to take in count that we are finding the interval 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:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

Part a

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)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

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

Since we don't have prior information about the population proportion we can use ase estimator $\hat p =0.5$ . And replacing into equation (b) the values from part a we got:

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

And rounded up we have that n=2401

Part b

For thi case the estimator for p is $\hat p =0.07$

$n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

4 0

3 years ago