Alan Mangus Math April 15, 2012

 Purpose of the study (the research question): Can the age of adult male humans be used as a reliable predictor of the weight of adult males? Age will be the explanatory variable and weight will be the response variable.  Study design: I will be using an observational cross-sectional approach.

 Data collection: Since I do not have a population frame, I will be using Systematic Sampling. K = 10 with a random seed of =14, 14+10=24, 24+10=34 and so until a sample size of n=20 was reached. The survey was given to customers of Smith’s Market Place on March 24, 2012 in Salt Lake City, Utah.

Age of Adult MaleWeight (in lbs) of Adult Male

n = 20, ∑x = 70 Mean = 740/20 = 37 Standard Deviation = n = 20, ∑x = 3400 Mean = 3400/20 = 170 Standard Deviation = MinimumQ1MedianQ3MaximumMinimumQ1MedianQ3Maximum Range = = 45Range = 222 – 137 = 85 IQR = 42.5 – 27 = 15.5IQR = – 152 = 37.5 Mode = 27, 31, 39Mode = 154

Y = ax +b a = b = r = y = (x) Critical Value for Correlation Coefficient For n = 20 is r is less than is less than = No Linear Correlation

 Distribution of Histogram for age is skewed right.  Distribution of histogram for weight is skewed right.  Scatter diagram reveals almost no correlation between the two variables.  Furthermore the critical value for a sample size of 20 is The correlation coefficient for this survey was 0.137, well below the value needed for a positive correlation.

With such a low correlation between the explanatory variable and the response variable age would not be a very reliable predictor of weight in adult male humans. A more reasonable predictor might be height; which is why it is used in the Body Mass Index formula (BMI).