Turn on thread page Beta
 You are Here: Home >< Maths

# AS maths Binomial Distribution help!? watch

1. Q: A calculator claims it can randomly generate a digit from 0-9. For any 4 digits generated, the probabibility of 2 zeros is 0.03. Is the calculators claim correct?

A: No, if it was, the probability of 2 zeros would be 0.0486

How do you get this answer?
2. There are 10 digits altogether.

The prob of a 0 is 1/10, the prob of not getting = is 9/10

You need two zeros and two non-zeros, usual rules apply about multiplying the probabilities together. ------(1)

However, for 4 digits, there are actually 6 ways the zeros can appear. They could be eg the first two digits drawn, or they could be the first and third, or they could be the last two etc. In total, there are 6 ways (try it and see)

So your prob (1) above needs to be multipled by 6.

Turn on thread page Beta

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: February 20, 2018
Today on TSR

### Summer Bucket List is Back!

Start yours and you could win £150!

Poll
Useful resources

## Make your revision easier

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

Can you help? Study help unanswered threads

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE