Can someone help with the attached?

Can someone help with the attached? Below is the start of my answer.

Standard Deviation of Stock A        Answer: .00607    

.15+.25+.08+.16+.05 =.69/5=0.138

.15-0.138=-.012  .000144

.25-0.138=-.112   .012544

.08-0.1388=-0,058 - .003364

0.138-.16=--0.022   .000484

0.138-.05=-0.088 - .007744