2.1 Histograms and

Distribution Shapes

A histogram is a visual display of a frequency table Uses bars to represent the classes The width of the bars is the class width

Histogramheight→class frequency

Relative frequency Histogramheight→relative frequency

*Comment on class boundaries p.39 p.43 #1 c and d

Distribution Shapes p.42

c) Skewed left or Skewed right: one tail is stretched out longer than the other. The direction of skewedness is on the side of the longer tail (the tails “tail off”/decrease)

d) Bimodal: the two classes with the largest frequencies are separated by at least one class; sometimes indicates that we are sampling two populations

a) Symmetrical: both the left & right sides are (roughly) the same

b) Uniform or Rectangular:every class has equal frequency

Homework:

p. 45 #7, 8, and 11