# Estimation of mean and variance

#### Constantine

##### New Member
Good day,

I am looking for estimation of mean and variance for variable Y :

Where: n and N are both variables and could take any type of distribution ( continuous or discrete)

Suppose that we know the mean and varaince of both varaibles: n and N

Is any estimation exist for variance and mean?

Best regard !

#### Attachments

• 1 KB Views: 1

#### Dason

##### Ambassador to the humans
Your question doesn't make sense to me. It looks like your notation is all over the place.

#### Constantine

##### New Member
Hello,

In my case Y variable represent average demand during lead time. I consider demand and lead time as uncertain.

For example, when demand and lead time are constant and known:

Lead time: 4 days

Demand day 1: 150 units

Demand day 2: 200 units

Demand day 1: 250 units

Demand day 1: 150 units

Y= (150+200+250+150)/4= 187,7 unit / day.

But in my case, demand and lead time are uncertain.

Thank’s

#### Constantine

##### New Member

Where: di represents daily demand and N represents lead time.

#### Attachments

• 3.3 KB Views: 1
• 5 KB Views: 1