Which question is a statistical question?

) To estimate weight of a certain product, 100 of these products are measured. The average weight and standard deviation are cal

inessss [21]

Answer:

a) $P(X$

And we can find this probability with the normal standard table or excel and we got:

$P(z$

And we would expect about 0.02275*10000 =227.5 rejected and 2.75 in the sample of 100 selected

b) $P(39$

And we can find this probability with this difference:

$P(-1$

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

$P(-1$

And we expect about 0.819*10000= 8190 and 81.9 in the sample od 100 selected

c) $40-1.64\frac{1}{\sqrt{100}}=39.836$

$40+1.64\frac{1}{\sqrt{100}}=40.164$

So on this case the 90% confidence interval would be given by (39.836;40.164)

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:

$X \sim N(40,1)$

Where $\mu=40$ and $\sigma=1$

We are interested on this probability

$P(X$

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:

$P(X$

And we can find this probability with the normal standard table or excel and we got:

$P(z$

And we would expect about 0.02275*10000 =227.5 rejected and 2.75 in the sample of 100 selected

Part b

$P(39$

And we can find this probability with this difference:

$P(-1$

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

$P(-1$

And we expect about 0.819*10000= 8190 and 81.9 in the sample od 100 selected

Part c

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

Now we have everything in order to replace into formula (1):

$40-1.64\frac{1}{\sqrt{100}}=39.836$

$40+1.64\frac{1}{\sqrt{100}}=40.164$

So on this case the 90% confidence interval would be given by (39.836;40.164)

5 0

3 years ago

Can someone help me with this question? Thanks!

alex41 [277]

<h3>Answer: 50%</h3>

You won't type in the percent sign since it's already taken care of by your teacher.

===========================================================

Explanation:

We know 100% that a fruit was chosen first. That means the three original fruits drops down to 3-1 = 2 fruits.

There are 2 fruits left and 2 vegetables. That gives 2+2 = 4 items to pick from for the second slot.

We have 2 things we want (those vegetables) out of 4 items to pick from. The chances of getting a vegetable here is 2/4 = 1/2 = 0.50 = 50%

------------------

This is an optional section, but here's another way to look at it. This method is slightly longer.

Let A,B,C be the three fruits and D,E be the two vegetables.

Here are all of the ways to have a fruit chosen first followed by a vegetable

AD and AE
BD and BE
CD and CE

There are m = 3*2 = 6 ways to do this.

Now consider all of the ways to have a fruit first (either A,B, or C) and the second slot can be a fruit or a vegetable.

Here are all of the ways to do that

AB, AC, AD, AE
BA, BC, BD, BE
CA, CB, CD, CE

Each row has 4 items, so we have n = 3*4 = 12 different ways to have a fruit go first and the second item is a fruit or a vegetable.

Therefore, m/n = 6/12 = 1/2 = 0.5 = 50% is the probability of getting a vegetable second given that a fruit was chosen first.

7 0

2 years ago

Help me fast need help plz <br>I will give you brain list<br>Work out the value of x

alex41 [277]

Someone put the link to something

5 0

3 years ago

3x≤−5/4 please help me so i can pass this assignment

RSB [31]

Hope this helps !!!!!

6 0

3 years ago

PLEASE HELP ASAP!!!!

musickatia [10]

Answer:

An independent clause is a group of words that contains both a subject and a predicate. It expresses a complete thought and can stand alone as a sentence. It can also be joined to other dependent or independent clauses to make a more interesting and complex sentence.

Step-by-step explanation:

8 0

3 years ago