A study showed that 76% of the participants had good results using the drug. What fraction of the participants had good results?

An engineer is going to redesign an ejection seat for an airplane. The seat was designed for pilots weighing between 130 lb and

egoroff_w [7]

Answer:

a) $P(140$

$P(0.036$

b) $P(140< \bar X$

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

$X \sim N(139,28.1)$

Where $\mu=139$ and $\sigma=28.1$

We are interested on this probability

$P(140$

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

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

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

$P(140$

And we can find this probability like this:

$P(0.036$

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

$P(0.036$

Part b

For this case we select a sample size of n =32. Since the distribution for X is normal then the distribution for the sample mean $\bar X$ is given by:

$\bar X \sim N(\mu=139, \frac{\sigma}{\sqrt{n}}=\frac{28.1}{\sqrt{32}}=4.97)$

And the new z score would be:

$Z=\frac{\bar X -\mu}{\sigma_{\bar x}}$

$P(140< \bar X$

5 0

3 years ago

I need help with this

Harlamova29_29 [7]

Answer:

50 degrees.

Step-by-step explanation:

The three angles make up a straight line angle which = 180 degrees, so:

C = 180 - 65 - 65

= 50 degrees.

7 0

2 years ago

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If sin x = .42, what is cos x?

34kurt

From the identity,
sin^2(x)+cos^2(x)=1
then
cos(x)=sqrt(1-sin^2(x))
where sin(x) is given as 0.42.

Note that the above answer applies to 0<x<90 degrees

6 0

3 years ago

Please help me thanks if u do

aniked [119]

Answer: a

Step-by-step explanation: look at the chart

3 0

3 years ago

In a local election 138,201 people voted for the winning candidate. If she won by 29,288 votes, about how many votes did the oth

max2010maxim [7]

You have to use subtraction because it says how many

3 0

3 years ago

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