George Fastrack, head of the Bureau of Obfuscation’s United Way drive, wants to know the average United Way pledge among Obfuscation Bureau employees ( pledges are normally distributed). George takes a sample of 10 and gets the results shown in the accompanying table. What is George’s best estimate of the mean donation? What is George’s best estimate of the standard deviation of the donations? Between what two values can George be 95% sure the mean value lies?
Person Pledge
1 ……………...... $ 25
2 ……………...... 0
3 ……………...... 35
4 ……………...... 100
5 ……………...... 0
6 ……………...... 0
7 ……………...... 15
8 ……………...... 50
9 ……………...... 25
10 ……………...... 50