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3 years ago

Help with math question plz. 12th grade

Mathematics

1 answer:

leonid [27]3 years ago

4 0

Answer:

Step-by-step explanation:

To find the volume of a rectangular prism, you need to multiply the width by the length by the height (the three given side lengths).

Only C and D do that. Meanwhile A and B just add them, which is not what you're supposed to do.

So, we know it's not A or B.

After finding the volume of each of the prisms, you need to add them to find the combined volume.

D multiplies them, so it's not D.

Therefore it must be C, which correctly multiplies the side lengths and then adds the volumes together at the end.

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Ten young adults living in California rated the taste of a newly developed sushi pizza topped with tuna, rice, and kelp on a sca

timurjin [86]

Answer: For California: μ = 33.1; σ² = 1120.50; Range = 32;

For Iowa: μ = 24.5; σ² = 32.73; Range = 19

Step-by-step explanation:

Mean is the average of a population or a sample. It is defined as

μ = ∑x / n, where

x is each number of the set;

n is the total individuals in the sample.

Calculating the Mean for sample of taste of pizza in California:

μ₁ = $\frac{34+39+40+46+33+31+34+14+15+45}{10}$ = 33.1

Calculating the Mean for the sample in Iowa:

μ₂ = $\frac{28+25+35+16+25+29+24+26+17+20}{10}$ = 24.5

Variance measures how far the number in the set is from the mean. Its formula is

σ² = (∑x-μ)² / n -1

which means to find the variance, you have to get the difference between the number and the mean, square the result, add all of them and then divide by (n-1) individuals.

The Variance for the sample in California is

σ² = $\frac{(34 - 33.1)^{2}+(39-33.1)^{2}+(40-33.1)^{2}+(46-33.1)^{2}+(33-33.1)^{2}+(34-33.1)^{2}+(14-33.1)^{2}+(15-33.1)^{2}+(45-33.1)^{2}}{9}$ σ² = 120.50

The Variance for the sample in Iowa is

σ² = 32.73

Range is the difference between the highest and the lowest number of the set: range = highest - lowest

For the sample in California, the Range is

range = 46 - 14 = 32

For the sample in Iowa:

range = 35 - 16 = 19

For California:

Mean = 33.1;
Variance = 120.50;
Range = 32;

For Iowa:

Mean = 24.5;
Variance = 32.73;
Range = 19;

6 0

3 years ago

Test scores of the student in a school are normally distributed mean 85 standard deviation 3 points. What's the probability that

Mrrafil [7]

Answer:

The probability that a random selected student score is greater than 76 is $\\ P(x>76) = 0.99865$ .

Step-by-step explanation:

The Normally distributed data are described by the normal distribution. This distribution is determined by two parameters, the population mean $\\ \mu$ and the population standard deviation $\\ \sigma$ .

To determine probabilities for the normal distribution, we can use the standard normal distribution, whose parameters' values are $\\ \mu = 0$ and $\\ \sigma = 1$ . However, we need to "transform" the raw score, in this case x = 76, to a z-score. To achieve this we use the next formula:

$\\ z = \frac{x - \mu}{\sigma}$ [1]

And for the latter, we have all the required information to obtain z. With this, we obtain a value that represent the distance from the population mean in standard deviations units.

<h3>The probability that a randomly selected student score is greater than 76</h3>

To obtain this probability, we can proceed as follows:

First: obtain the z-score for the raw score x = 76.

We know that:

$\\ \mu = 85$

$\\ \sigma = 3$

$\\ x = 76$

From equation [1], we have:

$\\ z = \frac{76 - 85}{3}$

Then

$\\ z = \frac{-9}{3}$

$\\ z = -3$

Second: Interpretation of the previous result.

In this case, the value is three (3) standard deviations below the population mean. In other words, the standard value for x = 76 is z = -3. So, we need to find P(x>76) or P(x>-3).

With this value of $\\ z = -3$ , we can obtain this probability consulting the cumulative standard normal distribution, available in any Statistics book or on the internet.

Third: Determination of the probability P(x>76) or P(x>-3).

Most of the time, the values for the cumulative standard normal distribution are for positive values of z. Fortunately, since the normal distributions are symmetrical, we can find the probability of a negative z having into account that (for this case):

$\\ P(z>-3) = 1 - P(z>3) = P(z$

Then

Consulting a cumulative standard normal table, we have that the cumulative probability for a value below than three (3) standard deviations is:

$\\ P(z$

Thus, "the probability that a random selected student score is greater than 76" for this case (that is, $\\ \mu = 85$ and $\\ \sigma = 3$ ) is $\\ P(x>76) = P(z>-3) = P(z$ .