The expression $${e^{ - ln\,x}}$$ for $$x > 0$$ is equal to

Consider the function $$\,\,y = {x^2} - 6x + 9.\,\,\,$$ The maximum value of $$y$$ obtained when $$x$$ varies over the interval $$2$$ to $$5$$ is

Consider a Gaussian distributed random variable with zero mean and standard deviation $$\sigma .\,\,\,$$ The value of its cumulative distribution function at the origin will be

A random variable is uniformly distributed over the interval $$2$$ to $$10.$$ Its variance will be