Advanced Math Topics 2.4 Cumulative Frequency Histograms & Polygons If you do not use stem and leaf add the part about misleading graphs to this ppt

Normal Curve A radar set up on Highway 580 for one hour clocked and recorded car speeds between 52 and 82 mph. The scatter plot is shown below. How will the graph look? FREQUENCYFREQUENCY This is an example of a normal curve (normal distribution), Also known as the “Bell Curve.” Many things that occur in nature have a normal distribution.

Would these have a normal distribution? The useful life of an auto battery with time along the horizontal axis. Yes! The number of students per class with # of students on the horizontal axis. Depends, some classes(PE) may throw it off)! The attendance at AT&T Park for Giants with the amount of people on the horizontal axis. No, the attendance is too consistent!

Steps to Create a Cumulative Frequency Histogram 1)C reate a new column “Cumulative Total.” Add all previous frequencies and put this number in the row. 2) Follow the steps to create a histogram

Cumulative Frequency Histogram Weights of 250 Army Recruits Weight (lbs.) Frequency Sometimes we ask questions like… “How many are less than or equal to a certain measurement?” We can answer this by accumulating the frequencies. Cumulative Frequency = = = = Cum. Freq How many recruits weighed 170 lbs. or less? Weight Cumulative frequency histogram: a histogram displaying accumulated figures

Steps to Create a Cumulative Frequency Polygon 1)F ind the cumulative total for each row 3) Place a point for each cumulative frequency on the right side of the interval Why the right? Because the frequency includes all numbers at or below the highest number in the interval 4) Connect the points 2) Create axis and intervals just like a histogram

Cumulative Frequency Polygon Cum. Freq Weights A line graph that answers the question “How many recruits weigh less than or equal to a certain weight?” Create the same axes and scales, place a point on the upper limit for each interval at its cumulative frequency and connect them There were 125 recruits 160 lbs. or under. There were 0 recruits 130 lbs. or under Cumulative Frequency = = = = 250

Assignment Assignment P. 61 – 67 #3, 4, 12, 14a, 14b, 15 Together P. 67 #14a Together P. 67 #14a We have 3 missing protractors