 # 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.

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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? 6668 646260 7678 7472708280 56585452 FREQUENCYFREQUENCY 200 400 600 800 1000 1200 1400 1600 1800............................ 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! http://sports.espn.go.com/mlb/attendance

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 131-140 141-150 151-160 161-170 171-180 23 43 59 69 56 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 23 23 + 43 = 66 66 + 59 = 125 125 + 69 = 194 194 + 56 = 250 131-140 141-150 151-160 161-170 171-180 Cum. Freq. 40 80 120 160 200 240 280 23 66 125 194 250 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 131-140 141-150 151-160 161-170 171-180 Cum. Freq. 40 80 120 160 200 240 280 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. 23 66 125 194 250 Cumulative Frequency 23 23 + 43 = 66 66 + 59 = 125 125 + 69 = 194 194 + 56 = 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