# Excel - Statistics

#### VECTOR

##### New Member
In your formula you have = -$B$s3*LN( 1- A15) it should simply be = -2*LN( 1- A15)

So you insert “2” as the population mean. (Try some other values like 5 and 9) The mean of many values should be around 2.

Create in one row 2 uniformly distributed values. Transform that to 2 exponentially distributed values on the same excel row. Copy that downwards till 100 rows. Calculate the histogram.

(Or create the exponentially distributed values directly by = -2*LN( 1- RAND())

Do the same for 3 random values etc.

Hi!

I Think I managed to do it now, please see the Pictures I did above (The Pictures are from the task where one should do 5). THUS
There is something here that is not right, look at my histogram, the closer they get to zero, they should not look like that then…?

Also; please note that what I mean with SD in the Exel is σx (just not possible to do the symbol in the Excel at the time)

Wish you the best

#### VECTOR

##### New Member
Also note that there are 3 Pictures- might miss them if one does not look carefully

#### GretaGarbo

##### Human
You are improving!

But you should use this to standardize.

z = (y_bar - mu)/(sd/sqrt(n))

Note that the standarddeviation in the MEAN is sd/sqrt(n).

#### VECTOR

##### New Member
Haha thank you! I feel bad for My teacher on the other hand as he Will receive the work tonight, he Will probably loose his mind.

Regarding what you stated above;
What is y_bar?

When it comes to the mean:
Then Sd = sqrt(lambda) and (n)= 100,
or is n=5? (as for in this example where I used 5 “rows”, see picture)

Thank you once again! Feels like it starts to loosen up a Little bit, even though I’m still a hopeless wreck.

#### GretaGarbo

##### Human
y_bar is the mean of a variable y.

Then Sd = sqrt(lambda)
yes.

But the n is 5.

you take 5 random numbers and compute the mean. Then you do a histogram of 100 such means.

#### VECTOR

##### New Member
y_bar is the mean of a variable y.

yes.

But the n is 5.

you take 5 random numbers and compute the mean. Then you do a histogram of 100 such means.

Thank you!

Thus, I asked my teacher as well when I handed it in, according to him there is no Y bar in this test?

#### GretaGarbo

##### Human
You can call your variables whatever you want, y, t, x, s or anything. So x_bar normally mean the mean of x. jag thought that was obvious, at least for your teacher.

Now, what have you learnt from this experience?

#### VECTOR

##### New Member
Thank you!

So i do this:

I Find the standardisera by:
z = (x_bar - mu)/(sd/sqrt(n))
Where
X_bar = mean of x

Standarddev of mean = sd/sqrt(n).
Where n=in his case 5
Sd= sqrtLambda
X_bar is in this case the mean from the randomized Numbers (as you see in the pics)

??

#### VECTOR

##### New Member
I have now done just as stated as above.
In this case I did the "first task" that the teacher asks me to do with 2 random numbers.
I have made sure that you can see the Formulas for each row- just see the Pictures.

How does it look?

#### Attachments

• 66.2 KB Views: 1
• 64.4 KB Views: 1
• 65.2 KB Views: 1

#### VECTOR

##### New Member

Wonderful!

I posted an correction as well ^^

#### GretaGarbo

##### Human
Now, what have you learnt from this experience?
When you sample n=40, what is your conflusion about the distribution?

Why did they ask you to do this exercise?

#### VECTOR

##### New Member
When you sample n=40, what is your conflusion about the distribution?

Why did they ask you to do this exercise?

I have not yet done more than n=2 as I wanted to check with you that I do correctly from the start!
But will do first thing in the morning tomorrow as It seems ok! !

The reason for why they did want me to do this task (Note; my thoughts) is to let me to understand/develop an understanding on how for eg an histogram (collected data) is changing due to increased number of samples.
What I have learned (SO FAR) is that it seems like the more samples that are made, the more they move on to the "mean" of the sample.

Wish you a nice day and talk to you tomorrow!
I have catched fever and since I need to get the task done on Thursday and study for an exam on saturday- I need to get better "asap"

#### VECTOR

##### New Member
When you sample n=40, what is your conflusion about the distribution?

Why did they ask you to do this exercise?

I have done it now and it just totally slaughtered me. Nothing happens at my histograms....
Im posting Pictures of the histograms as well of how I have used the Formulas in the case of N=10.

#### Attachments

• 135.6 KB Views: 0
• 136 KB Views: 0
• 133.7 KB Views: 0
• 136.6 KB Views: 0
• 136.2 KB Views: 0

And more files:

#### Attachments

• 169.5 KB Views: 1
• 169.5 KB Views: 1
• 169.8 KB Views: 1
• 170.2 KB Views: 1