Question 4 Given the variance \( \sigma^{2} \) of 40 for a data set, what is the standard deviation \( \sigma \) ?

(1 point) Monday's lecture went over a logistic equation: \( f(t)=\frac{1000}{1+999 e^{-0.603 t}} \) which models how many people \( f \) have had the flu \( t \) days after an initial infection in a community of 1000 people. According to the model, how many people will have had the flu after 10 days? 294 According to the model, how many people will have had the flu after 20 days? According to the model, how many days until 500 people have had the flu? 11.45 According to the model, how many days until 700 people have had the flu? According to the model, how many days until 2000 people have had the flu? never Hint: One of your answers should be "never"

4. \( \int(x) \arctan (x) d x \)

\( x\left[\begin{array}{ll}x & 7 y \\ z & 4\end{array}\right]=\left[\begin{array}{rr}16 & 28 \\ 13 & 4\end{array}\right] \) \( x=16 \) (Simplify your answer.) \( y=4 \) (Simplify your answer.) \( z= \) (Simplify your answer)

Simplify the expression: \( (3 j+1)(3)=\square \)

7. Representa cada situación como una multiplicación de números racionales. Luego resuélvela En un colegio, \( \operatorname{los} \frac{2}{5} \) de estudiantes son hom- bres y de ellos \( \frac{1}{2} \) están en bachillerato. :Qué fracción representa a los hombres que hay en bachillerato?