Find the probability mass function of X
1. Determine whether each of the following random variables is discrete or continuous. a. The number of heads in 100 tosses of a coin. b. The length of a rod randomly chosen from a day's production. c. The final exam score of a randomly chosen student from last semester's engineering statistics class. d. The age […]
What is the smallest possible value for Y?
1. Candidates for a job are interviewed one by one until a qualified candidate is found. Thirty percent of the candidates are qualified. a. What is the probability that the first candidate is qualified? b. What is the probability that the first candidate is unqualified and the second candidate is qualified? c. Let X represent the […]
Find the mean and standard deviation of the length of time that four bulbs will last.
1. If X and Y are independent random variables with means μX = 9.5 and μY = 6.8, and standard deviations σX = 0.4and σY = 0.1, find the means and standard deviations of the following: a. 3X b. Y − X c. X + 4Y 2. The bottom of a cylindrical container has […]
Find the standard deviation of the thickness of an item.
1. Two batteries, with voltages V1 and V2 , are connected in series. The total voltage V is given by V = V1 + V2 . Assume that V1 has mean 12 V and standard deviation 1 V, and that V2 has mean 6 V and standard deviation 0.5 V. a. Find μV . Assuming […]
Find the standard deviation of the total volume of the beverage in the case.
1. The molarity of a solute in solution is defined to be the number of moles of solute per liter of solution (1 mole = 6.02 × 10 23 molecules). If X is the molarity of a solution of magnesium chloride (MgCl2 ), and Y is the molarity of a solution of ferric chloride (FeCl3 […]