Chapter 3 - Section 3.2 - Assess Your Understanding - Vocabulary and Skill Building - Page 151: 13

$R=1150~psi$ $s=459.65~psi$

$R=largest~data~value-smallest~data~value=4090-2940=1150$ The mean: $x̅=\frac{3960+4090+3200+3100+2940+3830+4090+4040+3780}{9}=3670$ The standard deviation: $s=\sqrt {\frac{Σ(x_i-x̅)^2}{n-1}}=\sqrt {\frac{(3960-3670)^2+(4090-3670)^2+(3200-3670)^2+(3100-3670)^2+(2940-3670)^2+(3830-3670)^2+(4090-3670)^2+(4040-3670)^2+(3780-3670)^2}{9-1}}=459.65$