To compute the necessary sample size for an interval estimate of ...

[AEWBW]

To compute the necessary sample size for an interval estimate of a population mean, all of the following procedures are recommended when  is unknown except
 a. use the estimated  from a previous study.
  b. use the sample standard deviation from a preliminary sample.
   c. use judgment or a best guess.
  d. use .5 as an estimate.

Question 2

If the lower control limit of a P chart is negative,
 a. a mistake has been made in the computations.
  b. use the absolute value of the lower limit.
  c. it is set to zero.
  d. it is an indication that the process is out of control.

[jasonq]

Answer to Question 1

d

Answer to Question 2

c

[AEWBW]

Gracias!

[frankwu0507]

Thanks for the timely response, appreciate it