Chapter 3: Normal Distributions

Question 1

Density Curve

Answer 1

-Smooth, approximation of data f/a histogram
Properties:
1) Always on/above horizontal axis
2) Total area underneath = 1
3) Median=equal areas point; point on hor axis that would divide area in 2
4) Mean=balance point if curve was made of solid material

Question 2

Rule for normal curves

Answer 2

68-95-99.7

• 68 % of obsvs fall w/in one SD from mean
• 95 fall w/in two SDs from mean
• 99.7 fall w/in three SDs from mean