AS AQA Mathematics Statistics 1B MS1B June 2014

Original post by sr234

Im not too sure about linear scaling, always seem to get the qs on it wrong :redface:

Well if u can post a question i will take a look :-)

Reply 61

U just have to think about it logically. Lets say u have petrol costs and u have calculated the mean and standard deviation. If the petrol cost went up by 50p for each value then the mean would also add 50p to it. As all values have 50p added there is the same difference or standard deviation as before. Bad example but if u can find a question its better

Reply 62

Original post by sr234

Im not too sure about linear scaling, always seem to get the qs on it wrong :redface:

When the values have multiplied by a number. The standard deviation AND mean also multiply by that number.
When the values have been added it's only the mean you need to change. Because all the numbers have just been translated so the spread remains unchanged

Reply 63

Original post by sr234

Im not too sure about linear scaling, always seem to get the qs on it wrong :redface:

If you look at question 1 (a)(ii) from June 2013 (it won't let me print screen it sorry)

The mean you would apply the full formula for
But the standard deviation would only need to times it by 5/9

Hope the helps

Reply 64

winniestar57

Original post by firsedge

If you look at question 1 (a)(ii) from June 2013 (it won't let me print screen it sorry)

The mean you would apply the full formula for
But the standard deviation would only need to times it by 5/9

Hope the helps

That's very helpful. I was wondering about that question! Thanks

Reply 65

winniestar57

And this was the question if anyone wants to have a look

1402050533326.jpg40.7KB

Reply 66

Original post by winniestar57

That's very helpful. I was wondering about that question! Thanks

No problem - if you need any more help just let me know.

Reply 67

junaid95

6

on probability questions when is it best to use a table?

Reply 68

Original post by junaid95

on probability questions when is it best to use a table?

Use the tables only when it is a binomial distribution question. And the question is to do with inequalities. If it is an equal to question your probably better to use the formula. Do you know the conditions for binomial distribution too?

Reply 69

The formula I'm on about us on page 11 of the formula booklet

Reply 70

junaid95

6

Original post by firsedge

Use the tables only when it is a binomial distribution question. And the question is to do with inequalities. If it is an equal to question your probably better to use the formula. Do you know the conditions for binomial distribution too?

sorry i worded that badly

when should we construct a table when answering a probability question, like what are the hints?

Reply 71

Original post by firsedge

Use the tables only when it is a binomial distribution question. And the question is to do with inequalities. If it is an equal to question your probably better to use the formula. Do you know the conditions for binomial distribution too?

N and p needed

Reply 72

Well u can find it says to use a table but if not then u can tell by

Reply 73