solution

 

. A leading agricultural company advertises that their bags of seeds contain at least a certain number of seeds. An SRS of bags from one warehouse is chosen, and these bags are opened and the number of seeds in each bag is counted. The actual counts are compared with the advertised target number of seeds. The difference is calculated as actual minus target, so that positive differences indicate bags that meet the advertising claim, and negative differences indicate bags that fall below the advertising claim. DATADATA

DATADATADATA

DATADATADATADATADATA

DATADATADATADATADATA

DATADATADATADATADATA

DATADATADATADATADATA

DATADATADATADATADATA

DATADATADATADATADATA

DATADATADATA

DATADATADATADATADATA

DATA FILE

SEEDTARGET

(a) Using the data file, create a histogram, a boxplot, and a Normal quantile plot of these data. What percent of these bags fall

below the advertised target?

(b) From inspecting the plots in part (a), comment on skewness, Normality, and the presence of outliers. Do any of your observations shed doubt on the appropriateness of using t procedures to analyze these data? Briefly explain your response.

(c) To assess its claim, the company accounts for the inherent variability in seed count by testing that the mean difference is at

least 500 seeds. Using an alpha of 0.05, perform this test making sure to specify the hypotheses and the P-value.

(d) The data include at least one negative outlier. If you were to exclude this outlier from the analysis, would your P-value

decrease or increase? Explain your response and support your explanation with a sketch.

(e) Redo the test with this low outlier excluded and verify your answer to part (d).