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3 years ago

Guys pls help me!!!!!

Mathematics

1 answer:

natima [27]3 years ago

3 0

Answer:

13 1/5 Kilometers

Step-by-step explanation:

you times 4 1/2 by 3 because if she runs 4 1/2 in a third of an hour then she runs 4 1/2 3 times every hour.

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A certain brand of rice costs $0.88 for 6.8 ounces.

Slav-nsk [51]

All you need to do is divide .88 by 6.8.

.88/6.8= 0.129 (round upt to .13 cents)

I hope this helps!

3 0

3 years ago

Read 2 more answers

You are making several purchases from the b-better electronics store. You can buy from this store online or in a physical store.

alexandr402 [8]

Answer:

Online Ordering is better.

Step-by-step explanation:

So you now that you save 20% if you to physical store and you save $20 if you go to the online store.

Say you are spending 100 dollars at the store to make it easy. 20% of one hundred is $20 so that is the same amount of money.

Now let’s look at the taxes and shipping so at the physical store you have to pay taxes no matter what but online you only do it if you purchase is less than $75 and we have $80 ($100–$20=$80) so at the physical store you have some amount of Mandy that is more than $80 because of taxes but if you buy online it will be exactly $80.

3 0

4 years ago

If the diameter of a circle changes from 18 cm to 6 cm, how will the circumference change?

olga_2 [115]

The circumference when the diameter is 18 = 18pi

The circumference when the diameter is 6 = 6pi

18pi/6pi=3

The circumference will become a third of what it was.

Hope this helps!

6 0

3 years ago

2+2=4 you should know this

nadya68 [22]

Ezzzzzzzzzzzzzzzzzzzzz

3 0

3 years ago

Read 2 more answers

A statistician calculates that 8% of Americans own a Rolls Royce. If the statistician is right, what is the probability that the

hichkok12 [17]

Answer:

0.007 = 0.7% probability that the proportion of Rolls Royce owners in a sample of 595 Americans would differ from the population proportion by more than 3%

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean $\mu = p$ and standard deviation $s = \sqrt{\frac{p(1-p)}{n}}$

A statistician calculates that 8% of Americans own a Rolls Royce.

This means that $p = 0.08$

Sample of 595:

This means that $n = 595$

Mean and standard deviation:

$\mu = p = 0.08$

$s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.08*0.92}{595}} = 0.0111$

What is the probability that the proportion of Rolls Royce owners in a sample of 595 Americans would differ from the population proportion by more than 3%?

Proportion above 8% + 3% = 11% or below 8% - 3% = 5%. Since the normal distribution is symmetric, these probabilities are equal, and so we find one of them and multiply by 2.

Probability the proportion is less than 5%:

P-value of Z when X = 0.05. So

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$Z = \frac{0.05 - 0.08}{0.0111}$

$Z = -2.7$

$Z = -2.7$ has a p-value of 0.0035

2*0.0035 = 0.0070

0.007 = 0.7% probability that the proportion of Rolls Royce owners in a sample of 595 Americans would differ from the population proportion by more than 3%

8 0

3 years ago