The annual earnings (in dollars) of 40 randomly selected intermediate level life insurance underwriters.

Use the data set to 

(a) Find the sample mean, 

(b) Find the sample standard deviation, and 

(c) Construct a 98% confidence interval for the population mean.

31,530 79,749 53,851 92,386 45,186 64,852 72,372 61,498 92,630 62,000 65,504 62,355 44,100 73,498 59,171 40,991 70,008 37,570 47,075 37,682 84,368 40,257 74,415 63,601 39,446 59,610 45,225 40,161 91,934 51,608 81,686 76,180 71,477 42,612 56,210 84,443 34,487 70,809 81,521 69,040