Multiple samples of students were asked four questions , with the sampling variablility of their answers to question 3 being the highest . Question 2 had the second highest sampling variability, question 1 came next , and finally question 4 had the lowest sampling variability, the answers to which of the questions are most reliable?

Which of the following expressions are equivalent ?

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

Weekly wages at a certain factory are normally distributed with a mean of $400 and a standard deviation of $50. find the probability that a worker selected at random makes between $450 and $500