What is the simplified form of ? 12x6 12x18 72x6 72x18

A school principal wants to find out if his school needs more bike racks. a survey is taken of 30 students who ride their bikes

Sergio039 [100]

Hello there.

Question: A school principal wants to find out if his school needs more bike racks. a survey is taken of 30 students who ride their bikes to school. why might the sample be biased?

Answer: It might be biased as the survey was only taken of students who ride their bikes to school. It is most likely that they would agree to it. To make it fair they survey should have been taken of a variety of different students.

Hope This Helps You!
Good Luck Studying ^-^

7 0

2 years ago

How do i solve this? and what’s the answer?

Vika [28.1K]

Im pretty sure x y should be 30, I hope this helps.

6 0

2 years ago

Piper is deciding whether she should pursue an education in engineering or in public communications. She has researched that a p

arlik [135]

Answer:

A public communications director would make $1,196,800 over a period of 20 years.

Step-by-step explanation:

The median salary of an engineer is $73,400 per year.

Piper has researched that a public communications director makes $13,560 less than this. (so we need to take this amount from the salary of an engineer)

Therefore, we would have that a public communications director would make

73,400 - 13,560 = $59, 840 per year

Now, the problem asks us how much a public communications director will make over a period of 20 years, thus, we have to multiply the amount she will get per year by 20.

Thus, over 20 years she would make: 59,840 x 20 = $1,196,800

3 0

2 years ago

You have a credit card that has a balance of $3,589.90 and a credit limit of $5,000. If you have a good credit rating, how much

vesna_86 [32]

Answer:

$1107.55

Step-by-step explanation:

3,589.90 x .0590/12 = $17.65

3,589.90 + 17.65 =3,607.55

3,607.55 - 2,500 = $1,107.55

3 0

2 years ago

5. Decide if each of the following statements is true or false. Explain your reasoning in each case.

sertanlavr [38]

Answer:

a. The smaller the sample size, the smaller the margin of error.

False if we see the value for the sample size is on the denominator and if we decrease the value of n then increase the value for the margin of error since the margin of error and the sample size are inversely proportional, with the estimated proportion and the confidence level fixed values.

b. If the margin of error is 0.05 and the observed proportion of red chips is 0.45, then the true population proportion is likely to be between 0.40 and 0.50.

Correct. The confidence interval for the population proportion is given by:

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

Or equivalently:

$\hat p \pm ME$

And if we replace on this case we got:

$0.45-0.05=0.40$

$0.45 +0.05=0.50$

So then the true proportion is between 0.4 and 0.5 for this case.

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

The population proportion have the following distribution

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

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)

Now if we analyze the statements one by one we have this:

a. The smaller the sample size, the smaller the margin of error.

False if we see the value for the sample size is on the denominator and if we decrease the value of n then increase the value for the margin of error since the margin of error and the sample size are inversely proportional, with the estimated proportion and the confidence level fixed values.

b. If the margin of error is 0.05 and the observed proportion of red chips is 0.45, then the true population proportion is likely to be between 0.40 and 0.50.

Correct. The confidence interval for the population proportion is given by:

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

Or equivalently:

$\hat p \pm ME$

And if we replace on this case we got:

$0.45-0.05=0.40$

$0.45 +0.05=0.50$

So then the true proportion is between 0.4 and 0.5 for this case.

4 0

3 years ago