You are Here: Home >< Maths

# Standard Deviation Watch

1. The masses, xkg, of 50 bags of flour were measured and the results were summarised below

n=50 Σ(x-1.5)=1.4 Σ(x-1.5)^2=0.05

calculate the mean and the standard deviation,

we think the mean is 76.4 but not sure, any help would be greatly appreciated
2. (Original post by VeeOMGlob)
The masses, xkg, of 50 bags of flour were measured and the results were summarised below

n=50 Σ(x-1.5)=1.4 Σ(x-1.5)^2=0.05

calculate the mean and the standard deviation,

we think the mean is 76.4 but not sure, any help would be greatly appreciated
Yes, it's 76.4

Edit: Sorry, made a mistake. You need to divide that by 50 for the mean. Oops.
3. thank you!, and how would we approach the standard deviation?
4. (Original post by VeeOMGlob)
thank you!, and how would we approach the standard deviation?
Notice that the data has been coded, I'll call it Y, and it =X-1.5

This changes the mean, but not the variance, in this case.

So, you have

And find the variance of Y, and square root.
5. (Original post by VeeOMGlob)
thank you!
Corrected my previous post #2

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: April 15, 2013
Today on TSR

### What is the latest you've left an assignment

And actually passed?

### Simply having a wonderful Christmas time...

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

### 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

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.