Confidence interval

An inspector comes into a bakery and decides to measure the meat content of meat filled pastries. He chooses twelve meat pastries. The twelve's meat pastries' average weight was 236,8 grams and standard deviation 23,0 grams. a) Determine estimate for meat content's standard error of the mean.

b) Determine a confidence interval of 95% for the meat content of the pastries.

c) The owner of the bakery says that meat content average for one pastry is 250 grams. Do our calculations support that claim? Justify your answer.