Statistics scramble my brain...

Since , (this was done in a previous question) it follows that a 90% confidence interval for the expected ressponse at has endpoints where is the relised value of the slope and is the residual mean square.

Similarly, since , it follows that a 90% prediction interval for a new observation at has endpoints .

For the fuel consumtion data of an earlier problem we had and on 5 degrees of freedom.

i) Find a 90% confidence interval for the expectation of distance travelled on a 30 litres of petrol.

ii) Construct a 90% prediction interval for the distance travelled on a typical 30 litres of petrol.

I have so much work to do right now and this is boggling me tho its probably relatively simple. Please help!