E0410 Fundamentals of Statistics for Scientific Data Using R by Daria Sapunova, PhD student, RECETOX daria.sapunova@recetox.muni.cz Bohunice, D29, room 123 Repetition Mentimeter.com Association between multiple variables: quantification We have: multiple numerical and categorical variables Height Gender Smoker Weight Salary Education Urbanization Productivity Teenage girl measures height standing near marks on wall wanting to become tall Man paying online and receiving cashback to wallet Losing weight. Female nutritionist cartoon character. Slimming, weightloss, dieting. Counting calories. Overweight man with hamburger. No Smoking Sign City skyline concept illustration Online certification illustration Association between multiple variables: quantification Check mark and cross symbols in flat styles Check mark and cross symbols in flat styles Weight (kg) Height (cm) One-unit shift How much will change? ? man character standing icon man character standing icon +1 cm 0.87 kg Gender Association between multiple variables: quantification Male Female Gender Height (cm) One-unit shift Weight (kg) ? How much will change? Male and female icon. Man and woman gender symbols. User avatars. Gentleman and lady. Male and female icon. Man and woman gender symbols. User avatars. Gentleman and lady. 2.14 kg Multiple linear regression The basic format of a multiple linear regression is: Y = α + β1*X1 + β2*X2 Where: Y = outcome (i.e. dependent) variable. X1 = first predictor (i.e. independent) variable. X2 = second predictor (i.e. independent) variable. α = intercept (average Y when X1=X2=0). Note: α is unit specific. β1 = slope of the line (change in Y for a 1 unit increase in X1 when X2 is held constant). Note: β1 is unit specific. β2 = slope of the line (change in Y for a 1 unit increase in X2 when X1 is held constant). Note: β2 is unit specific. https://www.coursera.org/learn/linear-regression-r-public-health; https://towardsdatascience.com/graphs-and-ml-multiple-linear-regression-c6920a1f2e70 Association between multiple variables: quantification We have: multiple numerical and categorical variables Fruit consumption; veggie consumption; fish consumption; meat consumption Mercury level Be aware: collinearity as an assumption in case of multiple numerical variables! Pollution toxic environment damage and global contamination flat isolated Bright vector illustration of colorful juicy orange isolated, organic citrus fruit vegetarian food menu Vintage fish illustration Set of pieces of meat of varying degrees of roasting Practical part