Problem. 11 : Find the value of the constant k such that the function is a. probability density function on the indicated interval. f[m)=k; Dgzgsi 2.3 a Problem. 19 : Find the mean, variance, and standard deviation of the random variable X associated with the probability density function over the indicated interval. f(z)=i; 153mg 33 (Round your answers to four decimal places if necessary.) meal] a variance standard deviation a Problem. 20 : The life span (in years] of a certain brand of laptop computer is a continuous random variable with probability density function t] =4(4+t2)\"3'2; USt