Please Help ME!!! What are the real zeroes of x3 + 6 x2 – 9x

Joses ACT score had a z-score of .75.what was his ACT score? mean score=21.1 sd=5.2

Zielflug [23.3K]

Answer:

$X \sim N(21.1,5.2)$

Where $\mu=21.1$ and $\sigma=5.2$

And the z score is given by:

$z = \frac{x -\mu}{\sigma}$

And since z = 0.75 we can replace like this:

$0.75 = \frac{x- 21.1}{5.2}$

And if we solve for x we got:

$x = 21.1 +0.75*5.2 = 25$

Step-by-step explanation:

Previous concepts

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".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the ACT scores of a population, and for this case we know the distribution for X is given by:

$X \sim N(21.1,5.2)$

Where $\mu=21.1$ and $\sigma=5.2$

And the z score is given by:

$z = \frac{x -\mu}{\sigma}$

And since z = 0.75 we can replace like this:

$0.75 = \frac{x- 21.1}{5.2}$

And if we solve for x we got:

$x = 21.1 +0.75*5.2 = 25$

6 0

3 years ago

Visa Card USA studied how frequently young consumers, ages 18 to 24, use plastic (debit and credit) cards in making purchases (A

umka2103 [35]

Answer:

Given the consumer is 18 to 24 years old, there is 37% probability that he uses a plastic card.

Step-by-step explanation:

This can be formulated as the following problem:

What is the probability of B happening, knowing that A has happened.

It can be calculated by the following formula

$P = \frac{P(B).P(A/B)}{P(A)}$

Where P(B) is the probability of B happening, P(A/B) is the probability of A happening knowing that B happened and P(A) is the probability of A happening.

In this problem, we have:

What is the probability of the consumer using a plastic card, given that the consumer is 18 to 24 years old.

The problem states that the probability that a consumer uses a plastic card when making a purchase is .37, so $P(B) = 0.37$

P(A/B) is the probability that the consumer being 18 to 24 years old, given that he uses a plastic card. The problem states that this probability is .19. So $P(A/B) = 0.19$

P(A) is the probability that the consumer is 18 to 24 years old. There is a .81 probability that the consumer is more than 24 years old. So there is a .19 probability that he is 18 to 24 years old. So $P(A) = 0.19$

The probability is

$P = \frac{P(B).P(A/B)}{P(A)} = \frac{0.37*0.19}{0.19} = 0.37$

Given the consumer is 18 to 24 years old, there is 37% probability that he uses a plastic card.

4 0

4 years ago

If you add Natalie’s age and Fred’s age, the result is 41. If you add Fred’s age to 3 times Natalie’s age, the result is 67. Fin

JulsSmile [24]

Answer:

Natalie is 13 years old, while Fred is 28 years old.

Step-by-step explanation:

Given that if you add Natalie’s age and Fred’s age, the result is 41, and if you add Fred’s age to 3 times Natalie’s age, the result is 67, to find how old Fred and Natalie are, the following calculation must be performed:

N + F = 41

3N + F = 67

(67 - 41) / 2 = N

26/2 = N

13 = N

13 x 3 + F = 67

39 + F = 67

F = 67 - 39

F = 28

28 + 13 = 41

Therefore, Natalie is 13 years old, while Fred is 28 years old.

4 0

3 years ago

Helpppppppppppp on number 19 20 21 22 23

Karolina [17]

19.q 20.d 21.6/7 22.6/7 23.b

3 0

4 years ago

Read 2 more answers

Find the domain and range of the function: f(t)=sec[((pi)t)/4]

beks73 [17]

The domain and range of the function f(t)=sec[((pi)t)/4] are the following:

Domain: All the real numbers except t = 2 + 4k, where k is an integer.

Range: (-∞, -1] U [1, ∞)

I am hoping that these answers have satisfied your queries and it will be able to help you in your endeavors, and if you would like, feel free to ask another question.

3 0

4 years ago

Please Help ME!!! What are the real zeroes of x3 + 6 x2 – 9x – 54?