4.14 Chapter 4 Review Questions

On this practice quiz, we're going to be referring to a data frame called SleepStudy. Below is a portion of the data frame as well as definitions of the variables included in it.

  Gender LarkOwl NumEarlyClass  GPA ClassesMissed CognitionZscore
1      0 Neither             0 3.60             0           -0.26
2      0 Neither             2 3.24             0            1.39
3      0     Owl             0 2.97            12            0.38
4      0    Lark             5 3.76             0            1.39
5      0     Owl             0 3.20             4            1.22
6      1 Neither             0 3.50             0           -0.04
  PoorSleepQuality DepressionScore Stress Happiness AllNighter
1                4               4 normal        28          0
2                6               1 normal        25          0
3               18              18 normal        17          0
4                9               1 normal        32          0
5                9               7 normal        15          0
6                6              14   high        22          0

• Gender 1=male, 0=female
• LarkOwl Early riser or night owl? Lark, Neither, or Owl
• NumEarlyClass Number of classes per week before 9am
• GPA Grade point average (0-4 scale)
• ClassesMissed Number of classes missed in a semester
• CognitionZscore Summary of performance on cognitive skills tests (continuous scores ranging from -1 to +1)
• PoorSleepQuality Measure of sleep quality (higher values are poorer sleep)
• DepressionScore Measure of degree of depression
• Stress Coded stress score: normal or high
• Happiness Measure of degree of happiness (higher values are happier)
• AllNighter Had an all-nighter this semester? 0 or 1