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3 years ago

Answer the following questions using what you've learned from this unit. Write your answers in the

Mathematics

1 answer:

sesenic [268]3 years ago

8 0

Answer:

x=-3

Step-by-step explanation:

5(x - 4) + 3x - 9x = 6 - (2x + 5) + 8x

(remove parentheses)

5x-20+3x-9x=6-2x-5+8x

(collect like terms and calculate)

-x-20=1+6x

(move the terms)

-x-6x=1+20

(collect like terms and calculate)

-7x=21

(divide both sides)

x=-3

(your answer :))

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HELP ME WITH THIS QUESTION PLEASE

lara [203]

Answer:

0.79

Step-by-step explanation:

all you really need to do is multiply your decimal (15.8) by your percent (5) so, you problem would look like 15.8(.05) (note it is .05 because there need to be 2 decimal places) so, your answer is .79

6 0

3 years ago

"A manufacturer of automobile batteries claims that the average length of life for its grade A battery is 55 months. Suppose the

STALIN [3.7K]

Answer:

$\\ P(z>-2) = 0.97725$ or P(x>49) is about 97.725% (or being less precise 97.5% using the empirical rule).

Step-by-step explanation:

We solve this question using the following information:

We are dealing here with normally distributed data, that is "the frequency distribution of the life length data is known to be mound-shaped".
The normal distribution is defined by two parameters: the population mean ( $\\ \mu$ ) and the population standard deviation ( $\\ \sigma$ ). In this case, we have that $\\ \mu = 55$ months, and $\\ \sigma = 3$ months.
To find the probabilities, we have to use the standard normal distribution, which has $\\ \mu = 0$ and $\\ \sigma = 1$ . The probabilities for this distribution are collected in the standard normal table, available in Statistics books or on the Internet. We can also use statistics programs to find these probabilities.
For most cases, we need to use the cumulative standard normal table, and for this we have to previously "transform" a raw score (x) into a z-score using the next formula: $\\ z = \frac{x - \mu}{\sigma}$ [1]. A z-score tells us the distance from the mean that a raw score is from it in standard deviations units. If this value is negative, the raw score is below the mean. Conversely, a positive value indicates that it is above the mean.
The cumulative standard normal table is made for positive values of z. Since the normal distribution is symmetrical around the mean, we can find the negative values of z using this formula: $\\ P(z$ [2].

Having all this information, we can solve the question.

<h3>The percentage of the manufacturer's grade A batteries that will last more than 49 months</h3>

First Step: Use formula [1] to find the z-score of the raw score x = 49 months.

$\\ z = \frac{49 - 55}{3}$

$\\ z = \frac{-6}{3}$

$\\ z = -2$

This means that the raw score is represented by a z-score of $\\ z = -2$ , which tells us that it is two standard deviations below the population mean.

Second Step: Consult this value in the cumulative standard normal table for z = 2 and apply the formula [2] to find the corresponding probability.

For a z = 2, the probability is 0.97725.

Then

$\\ P(z$

$\\ P(z2)$

But we are not asked for P(z<-2) but for P(z>-2) = P(x>49). This probability is the complement of the previous result, that is

$\\ P(z>-2) = 1 - P(z$

$\\ P(z>-2) = 1 - 0.02275$

$\\ P(z>-2) = 0.97725$

That is, the "percentage of the manufacturer's grade A batteries will last more than 49 months" is

$\\ P(z>-2) = 0.97725$ or about 97.725%

A graph below shows this result.

Notice that if we had used the 68-95-99.7 rule (also known as the empirical rule), that is, in a normal distribution, the interval between one standard deviation below and above the mean contains, approximately, 68% of the observations; the interval between two standard deviations below and above the mean contains, approximately, 95% of the observations; and the interval between three standard deviations below and above the mean contains, approximately, 99.7% of the observations, we could have concluded that 2.5 % of the manufacturer's grade A batteries will last less than 49 months, and, as a result, 1 - 0.025 = 0.975 or 97.5% will last more than 49 months.

We can conclude that with a less precise answer (but faster) because of the symmetry of the normal distribution, that is, 1 - 0.95 = 0.05. At both extremes we have 0.05/2 = 0.025 or 2.5% and we were asked for P(x>49) = P(z>-2) (see the graph below).

6 0

3 years ago

A. B. C. D. Whats the answer

icang [17]

I think it’s c not so sure tho

3 0

3 years ago

Read 2 more answers

Which is the answer. A B C D?

Harlamova29_29 [7]

Answer:

A) T'(-2,3), U'(0,5), V'(-1,0)

5 0

3 years ago

The length of time it takes to find a parking space at 9 A.M. follows a normal distribution with a mean of 5 minutes and a stand

erastovalidia [21]

Answer:

$z=0.524$

And if we solve for a we got

$a=5 +0.524*2=6.048 \approx 6.05 min$

Step-by-step explanation:

Let X the random variable that represent the lenght time it takes to find a parking space at 9AM of a population, and for this case we know the distribution for X is given by:

$X \sim N(5,2)$

Where $\mu=5$ and $\sigma=2$

For this part we want to find a value a, such that we satisfy this condition:

$P(X>a)=0.3$ (a)

$P(X$ (b)

As we can see on the figure attached the z value that satisfy the condition with 0.7 of the area on the left and 0.3 of the area on the right it's z=0.524

If we use condition (b) from previous we have this:

$P(X$

$P(z$

But we know which value of z satisfy the previous equation so then we can do this:

$z=0.524$

And if we solve for a we got

$a=5 +0.524*2=6.048 \approx 6.05 min$

3 0

3 years ago