Lesson # 10

Front 1

Imp point

Back 1

Many histograms are bell-shaped symmetric--these are modeled with a density curve called a normal distribution.

Front 2

Characteristics of a Normal Distribution

Back 2

1.Symmetric
2.Bell-shaped
3.One peak
4.Mean=Median

Front 3

Notation for Normal Distribution

Back 3

1.Mu=point of symmetry of normal distibution
2.Sigma=distance from the mean to the point where the curve begins to fall less steeply
3.Behind the mean we do:mu-sigma.
4.After the mean we do:mu+sigma

Front 4

Std.dev (mu)

Back 4

It is the distance from the mean(mu) to the point where the skier begins to decelerate. (see graph on CD)

Front 5

Animtion of Normal Distribution of changing MU

Back 5

MEAN:
1.If zero then it is symmetric
2.if mu>0 then graph moves on x axis to the right
3. If mu<0 then graph moves on x axis to the left

Front 6

Animtion of Normal Distribution of changing SIGMA

Back 6

1. Increase sigma then the graph's base covers more area on the x axis and it widens
2.Decrease sigma then the graph becomes thinner

Front 7

Importance of Normal Distribution

Back 7

1.Describes many distributions of real data and "chance" outcomes
2.Models many roughly sumetric distibutions for statistical inference

Front 8

Normal Distribution Areas

Back 8

68% of data lies within 1 std.dev of the mean
95% of data lies within 2 std.dev of the mean
99.7% of the data lies within 3 std.dev of MEAN

Front 9

Percentage of Area within intervals

Back 9

1.Subtract by previous percentage and then divide by half to get the area between tha particular interval

Front 10

Cumalative Area Percentages

Back 10

1.Add from left to right
2.It is the values that lie to the left of the values that the amount of percentages cover.