(Write down the measurement unit when applicable and correct your answers to 4 decimal places.) The following data was obtained in order to estimate the population mean number of patients consulting Dr. Tsang in a day. It is assumed that the number of patients in a day follows a Normal distribution. The table below shows the number of patients in a day for a sample randomly selected in September.

September 15 18 21 20 16 26 31 32 21 34

(a) Compile the sample mean and standard deviation of number of patients in a day. (2 marks)

(b) Calculate the sampling error at 95% confidence level for the estimation of the population mean number of patients in a day. (5 marks)

(c) Construct a 95% confidence interval for the population mean number of patients in a day. (3 marks) (Total: 10 marks)