The normal distribution

Question 1

What is a normal distribution?

Answer 1

• Bell-shaped and symmetrical theoretical distribution, with mean, median and mode coinciding at its peak and with frequencies gradually decreasing at both ends of the curve
• theoretical ideal distribution

Question 2

What is the total percentage under the normal curve?

Answer 2

Always 100%

Question 3

What is a standard normal distribution?

Answer 3

• distribution that occurs when a normal distribution has a mean of 0 and a standard deviation of 1

Question 4

What is a standard score or a Z score?

Answer 4

• the number of standard deviations that a given raw score is above or below the mean
• formula: Z = Xi - μ / σ
  where
  Xi is the raw score
  μ is the mean
  σ is standard deviation