7.3.1 - Video Example: Middle 80% of the z Distribution

Question: What z scores separate the middle 80% of the z distribution from the outer 20%?

  1. On a PC: from the menu select STATISTICS > Distribution Plot
    On a Mac: from the menu select Statistics > Probability Distributions > Distribution Plot
  2. Select Display Probability (Note: The default is the standard normal distribution)
  3. Select A specified probability
  4. Select Equal tails
  5. For Probability enter 0.20
Video Walkthrough