HELPPPPP !!!! Answer please and thank you

Ad libitum [116K]

Answer (quite straightforward):

650

= 65 x 10

4 0

3 years ago

Between which two ordered pairs does the graph of f(x) = 1/2x2 + x – 9 cross the negative x-axis? (–6, 0) and (–5, 0) (–4, 0) an

lbvjy [14]

Answer:

Between (-6,0) and (-5,0).

Step-by-step explanation:

When it crosses the x axis, it's an x-intercept. To find the x-intercept, set y (aka f(x)) to zero. The solutions to the equation are approximately 3.36 and - 5.36. Since you're finding the negative x-intercept, you only need the negative solution - 5.36. This is in between (-6,0) and (-5,0).

3 0

3 years ago

I need answer and work to please and thanks

Sergeu [11.5K]

Sorry i dont know this answer

3 0

4 years ago

A quality control expert at LIFE batteries wants to test their new batteries. The design engineer claims they have a variance of

iris [78.8K]

Answer:

The probability that the mean battery life would be greater than 533.2 minutes (in a sample of 75 batteries) is $\\ P(z>0.48) = P(x>533.2) = 0.3156$

Step-by-step explanation:

The main thing we have to take into account in this question is that we are about to find the probability of a sample mean. The distribution for sample means follows a normal distribution with mean $\\ \mu$ and standard deviation $\\ \frac{\sigma}{\sqrt{n}}$ . Mathematically

$\\ \overline{x} \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

For values of the sample $\\ n \ge 30$ , no matter the distribution the data come from.

And the variable z follows a standard normal distribution, and, as we can remember, this distribution has a mean = 0 and a standard deviation = 1. Mathematically

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

That is

$\\ z \sim N(0, 1)$

We have a variance of 3364. That is, a standard deviation of

$\\ \sigma^2 = 3364; \sigma = \sqrt{3364} = 58$

The population mean is

$\\ \mu = 530$

The sample size is $\\ n = 75$

The sample mean is $\\ \overline{x} = 533.2$

With all this information, we can solve the question

The probability that the mean battery life would be greater than 533.2 minutes

Using equation [1]

$\\ z = \frac{\overline{x} - \mu}{\frac{\sigma}{\sqrt{n}}}$

$\\ z = \frac{533.2 - 530}{\frac{58}{\sqrt{75}}}$

$\\ z = \frac{3.2}{\frac{58}{8.66025}}$

$\\ z = \frac{3.2}{6.69726}$

$\\ z = 0.47780$

With this value of z we can consult a cumulative standard normal table (or use some statistic program) to find the cumulative probability for z (and remember that this variable follows a standard normal distribution).

Most standard normal tables have values for z for only two decimals, so we can round the previous value for z as z = 0.48.

Then

$\\ P(z$

However, in the question we are asked for $\\ P(z>0.48) = P(x>533.2)$ . As well as all normal distributions, the standard normal distribution is symmetrical around the mean, and we have

$\\ P(z>0.48) = 1 - P(z$

Thus

$\\ P(z>0.48) = 1 - 0.68439$

$\\ P(z>0.48) = 0.31561$

Rounding to four decimal places, we have

$\\ P(z>0.48) = 0.3156$

So, the probability that the mean battery life would be greater than 533.2 minutes is (in a sample of 75 batteries) $\\ P(z>0.48) = P(x>533.2) = 0.3156$ .

5 0

4 years ago

What is the probability that a randomly selected permutation of the letters A, A, C, C, L, L, O, R, T, U would spell "calculator

kirill [66]

Answer:

See explanation

Step-by-step explanation:

Total number of letters = n! = 10

Permutation for 10 letters = n!

= 10!

= 10*9*8*7*6*5*4*3*2*1

= 3628800

From n letters:

Number of A = 2

Number of C = 2

Number of L = 2

A₁, A₂, C₁, C₂, L₁, L₂, O, R, T, U

Out of 3628800 permutations the word calculator can be spelled as:

C₁ A₁ L₁ C₂ U L₂ A₂ T O R

C₂ A₂ L₂ C₁ U L₁ A₁ T O R

and so on

So total number of different permutations are

(permutation of number of letters) / permutation of (number of As * number of Cs * number of Ls)

= 10! / (2! 2! 2 !)

= 10*9*8*7*6*5*4*3*2*1 / (2*1) (2*1) (2*1)

= 3628800 / 2 * 2 * 2

= 3628800 / 8

= 453600

Hence probability that a randomly selected permutation of the letters A, A, C, C, L, L, O, R, T, U would spell "calculator" is:

1 / total number of different permutations

= 1 / 10! / (2! 2! 2 !)

= 1/453600

= 0.000002

8 0

3 years ago