Statistics in an excel with data from a website.

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1. (Histogram, centrality, dispersion, quartiles, outliers) Acrylamide is a toxic encountered in several food products.1 The FDA (“U.S. Federal Drug Administration”) has surveyed the level of acrylamide across several different food products, and reported its results in the following website: http://www.fda.gov/food/foodborneillnesscontaminants/chemicalcontaminants/ucm053549.htm . This website has four different tables. The first table (“Table 1”) represents the results of the survey for a sample of food products collected on November 2002.

For this exercise, you are asked to use the data for the variable “Acrylamide (ppb)” that pertain to the food product “French fries” from Table 1. (“ppb” stands for “parts per billion.”) This should provide you with 53 observations. For those (and only those) observations:

(a) Use Excel to construct a relative histogram for the variable “Acrylamide (ppb).” Please provide brief and “to-the- point” comments on your results.

(b) Use Excel to calculate the following three measures of central tendency for the variable “Acrylamide (ppb)”: mean, median, and 5% trimmed mean (using the trimmed mean definition from the textbook). Do any of these measures of central tendency appear to not be appropriate for this particular dataset? Explain.

(c) Use Excel to calculate the following four measures of dispersion for the variable “Acrylamide (ppb)”: variance, standard deviation, mean absolute deviation, and coefficient of variation. Please provide brief and “to-the-point” comments on your results.

(d) Use Excel to calculate the first quartile, the third quartile, and the interquartile range for the variable “Acrylamide (ppb).” Please provide brief and “to-the-point” comments on your results.

(e) Use Excel to calculate the inner fences (left and right) for “Acrylamide (ppb),” and then the outer fences (left and right) for “Acrylamide (ppb).” Based on these calculated values, are there any “regular outliers” in the data? Any “extreme outliers” in the data? If so, which products are they?

(Note: In answering this question, please use the definition of “regular outlier” and “extreme outlier” provided on page 144 of the textbook, which is the same definition that was covered in class; please do not use the definition of “outlier” provided on pages 135-137 of the textbook.)

1 If interested, you may find out more about the health effects associated with acrylamide at: http://www.fda.gov/Food/FoodborneIllnessContaminants/ChemicalContaminants/ucm053569.htm .