(a) Suppose that monthly data on some time series variable exhibits
a clear upward trend but no seasonality. You decide to use a moving
average, with any appropriate span. Will there tend to be a
systematic bias in your forecasts? Explain why or why not. (b)
Under what circumstances can inventory be used as a hedge against
inflation? (c) Provide an example of when you might want to
take a stratified random sample instead of a simple random sample
and explain what the advantages of a stratified sample might
be. (d) Do you agree with the statement that nonresponse
errors can be overcome with larger samples? If you agree, explain
why. If you disagree, provide an example that backs up your
opinion. (e) When, if ever, is it appropriate to use the standard
normal distribution as a substitute for the t distribution with n –
1 degrees of freedom in estimating a population mean?