An article in the Journal of Agricultural Science ["The

Question

An article in the Journal of Agricultural Science ["The Use of Residual Maximum Likelihood to Model Grain Quality Characteristics of Wheat with Variety, Climatic and Nitrogen Fertilizer Effects" (1997, Vol. 128, pp. 135–142)] investigated means of wheat grain crude protein content (CP) and Hagberg falling number (HFN) surveyed in the UK. The analysis used a variety of nitrogen fertilizer applications (kg N/ha), temperature (ºC), and total monthly rainfall (mm). The data shown below describe temperatures for wheat grown at Harper Adams Agricultural College between 1982 and 1993. The temperatures measured in June were obtained as follows: 15.2 14.2 14.0 12.2 14.4 12.5 14.3 14.2 13.5 11.8 15.2

a Obtain two sided 99% for the true population mean

b Obtain lower 95% for the population mean

Answer 1

The first step is to determine whether we can assume normality. Make sure that when you graph, this looks roughly symmetrical. Then use your formula to standardize your average. Next, find your z-score and your confidence interval.