S1 Exam Question: what does 'Modeled by a Normal Random Variable' Mean?'

I'm having trouble understanding an exam question from a June 13 S1 paper and I was hoping for some clarification...

6. "The weight, X kilograms, of sand in a bag can be modelled by a normal random variable with unknown mean u and known standard deviation 0.4 .

(a) The sand in each of a random sample of 25 bags from a large batch is weighed. The total weight of sand in these 25 bags is found to be 497.5 kg

(i) Construct a 98% confidence interval for the mean weight of sand in bags in the batch.

(iii) State why use of the Central Limit Theorem is not required in answering part (a)(i).


Okay so does 'normal random variable' mean that it is normally distributed..?

and then it says state why CLT is not required...But it is because you have to use σ/√n in order to create a confidence interval..

I'm very sure I've misunderstood something fundamental but I'm not sure what..

Help appreciated!

I'm having trouble understanding an exam question from a June 13 S1 paper and I was hoping for some clarification...

6. "The weight, X kilograms, of sand in a bag can be modelled by a normal random variable with unknown mean u and known standard deviation 0.4 .

(a) The sand in each of a random sample of 25 bags from a large batch is weighed. The total weight of sand in these 25 bags is found to be 497.5 kg

(i) Construct a 98% confidence interval for the mean weight of sand in bags in the batch.

(iii) State why use of the Central Limit Theorem is not required in answering part (a)(i).


Okay so does 'normal random variable' mean that it is normally distributed..?

and then it says state why CLT is not required...But it is because you have to use σ/√n in order to create a confidence interval..

I'm very sure I've misunderstood something fundamental but I'm not sure what..

Help appreciated!

Which board is this? Is it by any chance, the S1, edexcel IAL?

Sorry i forgot to say its AQA

Oh alrighty! All the very best, all the same!