0 20 40 60 80 % Internet users 1.16 Stressed out, Part I. A study that surveyed a random sample of otherwise healthy high school students found that they are more likely to get muscle cramps when they are stressed. The study also noted that students drink more coffee and sleep less when they are stressed. (a) What type of study is this? (b) Can this study be used to conclude a causal relationship between increased stress and muscle cramps? (c) State possible confounding variables that might explain the observed relationship between increased stress and muscle cramps. , ling1.6 Smoking habits of UK residents. A survey was conducted to study the smoking habits of UK residents. Below is a data matrix displaying a portion of the data collected in this survey Note that "f" stands for British Pounds Sterling, "cig" stands for cigarettes, and "N/A" refers to a missing component of the data.36 marital grossIncome smoke sex age amt Weekends amt Weekdays Female 42 Single Under $2,600 Yes 12 cig/day 12 cig/day ONH Male 44 Single f10,400 to $15,600 No N/A N/A Male 53 Married Above $36,400 Yes 6 cig/day 6 cig/day 1691 Male 40 Single $2,600 to $5,200 Yes 8 cig/day 8 cig/day (a) What does each row of the data matrix represent? (b) How many participants were included in the survey? (c) Indicate whether each variable in the study is numerical or categorical. If numerical, identify as continuous or discrete. If categorical, indicate if the variable is ordinal