Adesign engineer wants to construct a sample mean chart for controlling the service life of a halogen headlamp his company produces. he knows from numerous previous samples that this service life is normally distributed with a mean of 500 hours and a standard deviation of 20 hours. on three recent production batches, he tested service life on random samples of four headlamps, with the following results: what is the standard deviation of the sampling distribution of sample means for whenever service life is in control? sample service life (hours. 1 495 500 505 500 2 525 515 505 515 3 470 480 460 470 select one: a. 10 hoursb. 6.67 hoursc. 11.55 hoursd. 5 hourse. 20 hours

Personal financial planning is the process of creating and achieving financial goals? true or false

Acoase solution to a problem of externality ensures that a socially efficient outcome is to

Stocks a, b, and c are similar in some respects: each has an expected return of 10% and a standard deviation of 25%. stocks a and b have returns that are independent of one another; i.e., their correlation coefficient, r, equals zero. stocks a and c have returns that are negatively correlated with one another; i.e., r is less than 0. portfolio ab is a portfolio with half of its money invested in stock a and half in stock b. portfolio ac is a portfolio with half of its money invested in stock a and half invested in stock c. which of the following statements is correct? a. portfolio ab has a standard deviation that is greater than 25%.b. portfolio ac has an expected return that is less than 10%.c. portfolio ac has a standard deviation that is less than 25%.d. portfolio ab has a standard deviation that is equal to 25%.e. portfolio ac has an expected return that is greater than 25%.