Presentation on theme: "Data and Distribution You will review/learn: ways of organizing discrete data recognize outlier describe distribution of data set."— Presentation transcript:
Data and Distribution You will review/learn: ways of organizing discrete data recognize outlier describe distribution of data set
Length of Calls in Minutes Number of Calls TallyFrequency 3/1 4///3 50 6//2 7////5 8//// //7 9////4 10/1 Tally Chart Look at this tally chart. How many 7 minute phone calls were made? 5 phone calls How do you know? There were 5 tally marks in the 7 minute row so the frequency was 5.
X X XX XXX XXXX XXXXX XXXXXXX Number of Phone Calls Length of Calls in Minutes Look at this line plot. How many 10 minute phone calls took place? 1 phone call
Where does most of the data cluster? What does this tell you? Most of the date clusters from 7 – 9 minutes. Most of the phone calls were 7 to 9 minutes long. Where is the gap in the line plot? What does this tell you? There is a gap at 5. No one made a phone call lasting 5 minutes. X X XX XXX XXXX XXXXX XXXXXXX Length of Calls in Minutes Number of Phone Calls
Stem and Leaf Plot A Stem and Leaf Plot is a method of organizing intervals or groups of data. Here is an example: Key: 3 | 6 = 36 A stem and leaf plot allows you to see easily the greatest, least, and median values in a set of data. It gives you a quick way of checking how many pieces of data fall in various ranges. It also lets you see the value of every piece of data.
How many students heights were measured? 19 students How many students are taller than 56 inches? 10 students What is the height of the tallest student? 63 inches What is the mode of the students heights? 57 inches What is the range of the students heights? 16 inches What is the median student height? 57 inches Key: 4 l 7 means 47 inches Look at this Stem and Leaf Plot and answer the questions.
Draw your own Stem and Leaf Plot Here is the information for your Stem and Leaf Plot. Yesterday, Tinas teacher kept track of how many ounces of milk each student drank in one day. Here is the data she collected: 12, 20, 8, 32, 24, 32, 36, 21, 28, 32. Dont forget a title for your graph. Remember to label!
Milk Drunk in One Day Key: 1 l 2 means 12 ounces
2/15/20149 Outliers data values that are either much larger or much smaller than the general body of data appears separated from the body of data on a frequency graph
2/15/ No outliers No high- leverage points Low leverage Outlier: big residual High leverag e outlier High- leverage outlier
2/15/ Example: outlier (3D) High leverage point
The Normal Distribution C A If the three histograms shown below represent the marks scored by students sitting 3 different tests, comment briefly on the difficulty level of each test. Left- Skewed Right- Skewed Symmetric al Easy Difficul t In test A most students scored high marks. In test B the marks are evenly distributed. B Normal In histogram B, most students found the test neither easy nor difficult. This type of distribution occurs often and is known as the NORMAL distribution. It is characterized by the bell-shaped curve that can be drawn through the top of each bar. In test C most students scored Low marks.
The Normal Distribution Which of the distribution below are approximately, normal, right or left skewed. A BC D EF G HI Right Skewed Left SkewedNormal Neither