Graded Homework

Problem 1.8

a. each row of data represents a case

b. 1691 participants were included in the study

c. sex: nominol categorical. age: continous numerical. marital: nominol categorical. gross income: continous numerical. smoke: ordinal categorical. amtWeekends: discrete numerical. amtWeekdays: discrete numerical

Problem 1.10

a. Population on interest: children between the ages of 5 and 15 who might cheat. Sample in study: 160 children.

b. Generalized? No, half of students were given istructions to act a certain way and offered a reward for a specific answer. Casual Relationship? No

Problem 1.28

a. No, it is unclear as to how many initial participants were surveyed after the 23 years. Additionally, it is unclear what the reporters means when they state, ‘adjusting for other factors’

b. This statement is not justified. The conclusion that can be drawn from this study is of the one-third of students who were identified as having problems with disruptive behavior or bullying, some of these students were likely to have some symptoms of a sleep disorder.

Problem 1.36

a. Randomized Experiment

b. Control: Participants asked to not exersice. Treatment: Twice a week exercise

c. Yes, the age groups are the blocking in this experiment.

d.No, participants would be aware of whether they were exercising or not.

e. Since we are unaware of the variables that are being tested in the mental health exam, we cannot conclude if there is a casual relationship. Since the samples is random, we can use it as a generalization on the population.

f. Yes, I would want to know if the participants of the study already took part in an exercise regime, what exactly was being measured for ‘mental health’, and how many participants we going to be apart of the experiement.

Problem 1.48

scores <- c(57, 66, 69, 71, 72, 73, 74, 77, 78, 78, 79, 79, 81, 81, 82, 83, 83, 88, 89, 94)
boxplot(scores, ylab = "Final Exam Score", xlab = "Intro Stats Class")

##Problem 1.50 ####a. This is a unimodal distribution. It matches box plot 3. ####b. This is a uniform distribution. It matches box plot 3. ####c. This is a unimodal distribution. It matches box plot 1.

Problem 1.56

a. right skewed, median is closer to first quartile. median would represent the typical observation of the data. Variability would be best described by IQR.

b. symmetrical, median price is situated equally between 1st and 3rd quartile. Median would represent the typical observation of the data. Variability would be best described by IQR.

c. Right skewed, with a natural boundary of zero alcoholic drinks. mean would represent the typical observation of the data. Variability would be described by standard deviation.

d. right skewed, with a natural boundary of zero income. median would represent the typical observation of the data. Variability would be described by IQR.

Problem 1.70

a. Survival is associated with transplate since some columns are divided in different vertical locations than others.

b. the box plot suggests that there is more variable data, lenght of days survival days, and therefore, more efficacy of the heart transplant.

c. Well, everyone dies at some point in their lives. so, all?

d. i) claim being tested is Ho: The heart transplate and survival are independent to each other. Ha: The heart transplate and survival are not independent to each other. ii) iii) We can conclude that the evidence is again the Ho (independance) model.