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4 years ago

6

Must READ! A multiple choice question on a test has 4 answer choices. You guess at the answer. What is the probability that you

will select the correct choice. write your answer as a percent. would the answer be 25%?

1 answer:

Furkat [3]4 years ago

4 0

Yep :) You're right!

The total probability of anything is always 100%, obviously.

If there are 4 choices, and you're equally likely to select either one, you can do 100% / 4 choices = 25%.

One of them have to be correct, so 1 of the 4 are bound to be right. 1/4 is also the same as 25%, hence you're correct! :)

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The answer is 4/7. see it from the multiple of 3...3*4 =12 and 3*7= 21. So this is the answer: 4/7.

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3 years ago

What is the slope and y intercept of the line y= 4x -12-2x?

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3 years ago

Read 2 more answers

A researcher reports survey results by stating that the standard error of the mean is 25 the population standard deviation is 40

bezimeni [28]

Answer:

a) A sample of 256 was used in this survey.

b) 45.14% probability that the point estimate was within ±15 of the population mean

Step-by-step explanation:

This question is solved using the normal probability distribution and the central limit theorem.

Normal probability distribution

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes 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.

a. How large was the sample used in this survey?

We have that $s = 25, \sigma = 400$ . We want to find n, so:

$s = \frac{\sigma}{\sqrt{n}}$

$25 = \frac{400}{\sqrt{n}}$

$25\sqrt{n} = 400$

$\sqrt{n} = \frac{400}{25}$

$\sqrt{n} = 16$

$(\sqrt{n})^2 = 16^2[tex][tex]n = 256$

A sample of 256 was used in this survey.

b. What is the probability that the point estimate was within ±15 of the population mean?

15 is the bounds with want, 25 is the standard error. So

Z = 15/25 = 0.6 has a pvalue of 0.7257

Z = -15/25 = -0.6 has a pvalue of 0.2743

0.7257 - 0.2743 = 0.4514

45.14% probability that the point estimate was within ±15 of the population mean

3 0

3 years ago

What is the third quartile, Q3, of the following distribution?

GREYUIT [131]

Answer:

The third quartile is:

$Q_3=29$

Step-by-step explanation:

First organize the data from lowest to highest

4, 5, 10, 12, 14, 16, 18, 20, 21, 21, 22, 22, 24, 26, 29, 29, 33, 34, 43, 44

Notice that we have a quantity of n = 20 data

Use the following formula to calculate the third quartile $Q_3$

For a set of n data organized in the form:

$x_1, x_2, x_3, ..., x_n$

The third quartile is $Q_3$ :

$Q_3=x_{\frac{3}{4}(n+1)}$

With n=20

$Q_3=x_{\frac{3}{4}(20+1)}$

$Q_3=x_{15.75}$

The third quartile is between $x_{15}=29$ and $x_{16}=29$

Then

$Q_3 =x_{15} + 0.75*(x_{16}- x_{15})$

$Q_3 =29 + 0.75*(29- 29)\\\\Q_3 =29$

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4 years ago

Read 2 more answers

A group of students and workers entering a metro station were asked whether they were riding the bus or the subway. the two-way

Otrada [13]

The addition of the row and column shows that the number of people polled will be 166.

<h3>How to calculate the number?</h3>

From the information given, the guest thing to do is to add the column. This will be:

= 48 + 118 = 166

Also, it's important to add the row. This will be:

= 69 + 97 = 166

Therefore, the number of people polled will be 166.

Learn more about column on:

brainly.com/question/1788884

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3 years ago