# Math Help - Normal distribution

1. ## Normal distribution

The weight of 1000 students in a secondary school has a normal distribution with a mean of 68.5kg and a standard deviation of 2.7kg. assume that the weight has been round up into one decimal place, how many students will be expected to have weight equal to 69.0kg?

I've tried P(68.9<X< 69.1) , and got 29

2. ## Re: Normal distribution

Hey Trefoil2727.

Using R I got the same answer you got:

> (pnorm(69.1,68.5,2.7)-pnorm(68.9,68.5,2.7))*1000
[1] 29.04248

Theoretically of course, the probability of getting exactly something in a continuous distribution is 0.

Are there any other assumptions that have been used?