Ihope some one can me!
the mean midday temperature recorded in june in a city in south california is 36_c, and the standard deviation is 3_c.
assuming the data is normally distributed, the number of days in june when the midday temperature was between 39_c and 42_c is?

Given that:
μ = 36 
σ = 3 

Standardize x to z = (x - μ) / σ 
P( 39 < x < 42) = P[( 39 - 36) / 3 < Z < ( 42 - 36) / 3] 
P( 1 < Z < 2) = P( x < 2) - P( x < 1)
                     = 0.9772 - 0.8413
                     = 0.1359 

(0.1359)(30)
= 4.0777
= 4 days

the angular velocity is the same for both.

Explanation:

Angular velocity is defined by the change in angle between time

          w = Δθ /Δt

As the arm and elbow are on the same axis the two rotate the same angles, therefore the angular velocity is the same for both.

This does not happen with linear speed

          v = w r

therefore as the hand has a greater radius its greater linear speed

Traalate

La velocidad angular es definida por el cambio del angulo entre el tiempo

w= Δθ/ΔDt

como el brazo y el codo están en el mismo eje los dos girar los mismo ángulos, por lo tanto la velocidad angular es la misma para los dos.

Esto no pasa con la velocidad lineal

          v = w r

por lo tanto como la mano tiene un radio mayor su velocidad lineales mayor