Questions from Engineering Statistics

Q: A soft-drink machine is regulated so that the amount of

A soft-drink machine is regulated so that the amount of drink dispensed averages 240 milliliters with a standard deviation of 15 milliliters. Periodically, the machine is checked by taking a sample of...

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

The heights of 1000 students are approximately normally distributed with a mean of 174.5 centimeters and a standard deviation of 6.9 centimeters. Suppose 200 random samples of size 25 are drawn from t...

Q: The random variable X, representing the number of cherries in a

The random variable X, representing the number of cherries in a cherry puff, has the following probability distribution: (a) Find the mean μ and the variance σ2 of X. b) Fin...

Q: If a certain machine makes electrical resistors having a mean resistance of

If a certain machine makes electrical resistors having a mean resistance of 40 ohms and a standard deviation of 2 ohms, what is the probability that a random sample of 36 of these resistors will have...

Q: The average life of a bread-making machine is 7 years

The average life of a bread-making machine is 7 years, with a standard deviation of 1 year. Assuming that the lives of these machines follow approximately a normal distribution, find (a) the probabili...

Q: The amount of time that a drive-through bank teller spends

The amount of time that a drive-through bank teller spends on a customer is a random variable with a mean μ = 3.2 minutes and a standard deviation σ = 1.6 minutes. If a random sample of 64 customers i...

Q: In a chemical process, the amount of a certain type of

In a chemical process, the amount of a certain type of impurity in the output is difficult to control and is thus a random variable. Speculation is that the population mean amount of the impurity is 0...

Q: A random sample of size 25 is taken from a normal population

A random sample of size 25 is taken from a normal population having a mean of 80 and a standard deviation of 5. A second random sample of size 36 is taken from a different normal population having a m...

Q: The distribution of heights of a certain breed of terrier has a

The distribution of heights of a certain breed of terrier has a mean of 72 centimeters and a standard deviation of 10 centimeters, whereas the distribution of heights of a certain breed of poodle has...

Q: A type of thread is being studied for its tensile strength properties

A type of thread is being studied for its tensile strength properties. Fifty pieces were tested under similar conditions, and the results showed an average tensile strength of 78.3 kilograms and a sta...