For a sample of100,000

pages of text randomly selected from books written in English since 1800, researchers recordedthe number of different letters from the alphabet that appear on each page. LetX

representthe the number of letters. The table below shows the probability distribution of the data. Find the mean and the standard deviation of the probability distribution using Excel.

• Round the mean and standard deviation to two decimal places.

"x" P(x)

1 0.08167

2 0.01492

3 0.02782

4 0.04253

5 0.12702

6 0.0228

7 0.02013

8 0.06091

9 0.06966

10 0.00153

11 0.00772

12 0.04025

13 0.02406

14 0.06749

15 0.07507

16 0.01929

17 0.00095

18 0.05987

19 0.06327

20 0.09056

21 0.02758

22 0.00932

23 0.0236

24 0.0015

25 0.01974

26 0.00074