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4 years ago

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daeshon is in the math club. there are 21 students in the club. the math teacher will pick 2 students at random to guide visitin

g students from colorado. what is the probability that daeshon will not be picked as a guide?

1 answer:

Firlakuza [10]4 years ago

3 0

Answer:

there are 19 unfavorable spots in 21 for Daeshon,

thus Pr = 19/21 [ B ] <----

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3 years ago

The Statistical Abstract of the United States published by the U.S. Census Bureau reports that the average annual consumption of

Karo-lina-s [1.5K]

Answer:

a) $P(\bar X$

b) $P(98$

c) $P(\bar X$

d) $P(93$

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".

Part a

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

$X \sim N(99.9,30)$

Where $\mu=99.9$ and $\sigma=30$

We select a random sample of n=36. And from the central limit theorem we know that the distribution for the sample is given by:

$\bar X \sim N(\mu =99.9 , \frac{\sigma}{\sqrt{n}}= \frac{30}{\sqrt{38}}=4.87)$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

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

If we apply this formula to our probability we got this:

$P(\bar X$

$=P(Z$

Part b

For this case we want this probability:

$P(98$

$=P(\frac{98-99.9}{\frac{30}{\sqrt{38}}}$

And we can find this probability on this way:

$P(-0.39$

And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.

$P(-0.39$

Part c

If we apply this formula to our probability we got this:

$P(\bar X$

$P(\bar X$

Part d

For this case we want this probability:

$P(93$

$=P(\frac{93-99.9}{\frac{30}{\sqrt{38}}}$

And we can find this probability on this way:

$P(-1.42$

And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.

$P(-1.42$

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Answer:

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2 years ago

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