Need some assistance with statistic question

1. Body Mass Index (BMI) is a measure used to determine whether someone is underweight, of normal weight, overweight, or obese. For 60-year old women in the United States, the standard deviation for BMI is 7. From a sample of 81 women, you have calculated a mean of 28 and a standard deviation of 7.2. 

a. What is the point estimate for the population mean? (2)

b. What is the error bound of the mean (EBM) for the 95% confidence interval? (2)

c. What values mark the 95% confidence interval? (2)  

d. What is the probability that the population mean falls outside of the calculated 95% confidence interval? (2)