21(2−x) 12x=44 I don't know what do what does X equal

13 + 2v - 8 + 6 > -7 - v please simplify and explain IN ONLY NUMBERS NO WORDS

insens350 [35]

Answer:

v > - 6

Step-by-step explanation:

13 + 2v - 8 + 6 > -7 - v (calculate the sum of difference)

= 11 + 2v>-7-v (move variable to the left-hand side and change its sign and move constant to the right-hand side and change its sign)

= 2v + v > - 7 - 11 (collect like items and calculate the difference)

= 3v>-18 (divide both sides of the inequality by 3)

=v > - 6

*in parentheses is written what to do to get the next number*

6 0

2 years ago

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g If a random sample of 18 deliveries was selected instead and the standard deviation of these delivery times was found to be 9.

lana [24]

Answer:

We can use the z score formula given by:

$z= \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}$

If we use this formula we got:

$z=\frac{21-20}{\frac{9.31}{\sqrt{18}}}= 0.456$

$z=\frac{25-20}{\frac{9.31}{\sqrt{18}}}= 2.279$

And using a calculator, excel or the normal standard table and we have that:

$P(0.456$

Step-by-step explanation:

We assume this previous info: It is known that the amounts of time required for room-service delivery at a certain Marriott Hotel are Normally distributed with the average delivery time of 20 minutes.

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 delivery times of a population, and for this case we know the distribution for X is given by:

$X \sim N(20,9.31)$