A Cadbury chocolate bar is advertised as containing 250 g of chocolate. From a

random sample of 20 Cadbury chocolate bars whose contents were accurately

measured by the South African Bureau of Standards (SABS), it was found that the

average weight was 245 g, with a sample standard deviation of 0,05 g. Assume that

the weight of a Cadbury bar is normally distributed.

1 What is the standard error if a 99% confidence level is used to estimate the

actual mean weight of all Cadbury chocolate bars?

(a) 0,00278 (b) 0,0025 (c) 0,01147 (d) 0,01118