1) You wish to know whether people with red hair contract the coronavirus at a lower rate than people with blond hair. You can?t do an experiment, clearly, but you can do an observational study. Which of the following can help you deal with the fact that you can?t use randomization to reduce the influence of confounding variables?

a) Ensuring a balanced design with an equal number of red and blond haired individuals

b) Including a few brown haired individuals

c) Getting as large a sample as possible

d) Matching pairs of blond and red haired individuals by things like age, sex, height, weight, location, etc.

2) You conduct an ANOVA test to determine whether rap, folk, country, or pop music genres record their music using more layers of sound.You calculate your F-value at an alpha of 0.05 and the appropriate degrees of freedom and it is 7.23. You find the critical value from the appropriate F-table and it is 7.56. Is it true or false that you reject your null hypothesis of no difference in the number of sound layers found in songs from the abovementioned music genres?

3) One challenge with ANOVA is that:

a) The alternative hypothesis doesn't specify which categories differ from which

b) The null hypothesis doesn't specify which categories differ from one which

c) The test is not very robust to heteroscedacity

d) The test is not very robust to deviations in normality

3) You are interested in knowing if grades are correlated with time spent on social media. You collect your sample and find a correlation coefficient of -0.64 with a P-value of 0.045. This means:

a) Decreased time on social media is associated with lower grades

b) Increased time on social media is associated with lower grades

c) Increased time on social media is associated with higher grades

d) Decreased grades are caused by spending more time on social media

4) You are interested in predicting the length of someone's nose on the basis of the number of lies a person tells per day (the Pinocchio hypothesis). You collect data from 100 random individuals and find that the mean number of lies told is 12 by age 25 (age limit for sample). Mean nose length among participants is 5.2 cm (bridge to tip). Based on the data, the slope of the relationship is 0.49. What is the y-intercept? (round to two decimal places).

5) You would like to test whether you can predict the amount of rain that falls on a given day from the amount of dancing a person does the day before.You randomly sample 50 people and record both dancing and raining, taking the average for each person over a 100 day period (one value for both dancing and rain per person). Each person was located in a different city more than 100 km distant from the closest other participant, to eliminate spatial autocorrelation.Neither your rain data nor your dancing data are normally distributed. What is the best solution?

a) Transform both variables using the best transformation for each

b) Transform both variables using the same transformation

c) Focus on transforming your dancing data, searching for a transformation that improves normality

d) Focus on transforming your rain data, searching for a transformation that improves normality