A projectile is launched at 37 degrees to the horizontal with a speed of 200 m/s from position A. How many seconds elapse after launch of the projectile before it returns to its original elevation at C?

Asynthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with mean 75.5 psi and standard deviation 3.5 psi. how is the standard deviation of the sample mean changed when the sample size is increased from n equals 8 to n equals 47