(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 degree of freedom in estimating a population means