Questions from Engineering Statistics

Q: A soft-drink machine is regulated so that it discharges an

A soft-drink machine is regulated so that it discharges an average of 200 milliliters per cup. If the amount of drink is normally distributed with a standard deviation equal to 15 milliliters, (a) wha...

Q: Consider the data in Exercise 8.2, find (

Consider the data in Exercise 8.2, find (a) the range; (b) the standard deviation. Exercise 8.2: The lengths of time, in minutes, that 10 patients waited in a doctor’s office before receiving treatme...

Q: The loaves of rye bread distributed to local stores by a certain

The loaves of rye bread distributed to local stores by a certain bakery have an average length of 30 centimeters and a standard deviation of 2 centimeters. Assuming that the lengths are normally distr...

Q: A research scientist reports that mice will live an average of 40

A research scientist reports that mice will live an average of 40 months when their diets are sharply restricted and then enriched with vitamins and proteins. Assuming that the lifetimes of such mice...

Q: The finished inside diameter of a piston ring is normally distributed with

The finished inside diameter of a piston ring is normally distributed with a mean of 10 centimeters and a standard deviation of 0.03 centimeter. (a) What proportion of rings will have inside diameters...

Q: Let us define / Show that

Let us define Show that and hence S’2 is a biased estimator for σ2.

Q: A lawyer commutes daily from his suburban home to his midtown office

A lawyer commutes daily from his suburban home to his midtown office. The average time for a one-way trip is 24 minutes, with a standard deviation of 3.8 minutes. Assume the distribution of trip times...

Q: In the November 1990 issue of Chemical Engineering Progress, a study

In the November 1990 issue of Chemical Engineering Progress, a study discussed the percent purity of oxygen from a certain supplier. Assume that the mean was 99.61 with a standard deviation of 0.08. A...

Q: The average life of a certain type of small motor is 10

The average life of a certain type of small motor is 10 years with a standard deviation of 2 years. The manufacturer replaces free all motors that fail while under guarantee. If she is willing to repl...

Q: The heights of 1000 students are normally distributed with a mean of

The heights of 1000 students are normally distributed with a mean of 174.5 centimeters and a standard deviation of 6.9 centimeters. Assuming that the heights are recorded to the nearest half-centimete...