4 The weights of packets of sultanas may be assumed to be normally distributed with a standard deviation of 6 grams.
The weights of a random sample of 10 packets were as follows:
\(\begin{array} { l l l l l l l l l l } 498 & 496 & 499 & 511 & 503 & 505 & 510 & 509 & 513 & 508 \end{array}\)
- Construct a \(99 \%\) confidence interval for the mean weight of packets of sultanas, giving the limits to one decimal place.
- State why, in calculating your confidence interval, use of the Central Limit Theorem was not necessary.
- On each packet it states 'Contents 500 grams'.
Comment on this statement using both the given sample and your confidence interval.
- Given that the mean weight of all packets of sultanas is 500 grams, state the probability that a 99\% confidence interval for the mean, calculated from a random sample of packets, will not contain 500 grams.