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Contingency Tables

Contingency Tables. Christopher Hamelin Keval Patel Jerome Stewart. What is a Contingency Table?. A contingency table is a graph or tablet that uses frequencies divided into rows and columns that will summarize the relationship between variables in a given problem.

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Contingency Tables

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  1. Contingency Tables Christopher Hamelin Keval Patel Jerome Stewart

  2. What is a Contingency Table? • A contingency tableis a graph or tablet that uses frequencies divided into rows and columns that will summarize the relationship between variables in a given problem. • Contingency table is to determine that event A and B is either not or is an independent variable. • Contingency table summarises categorical data, which includes percentages in each of the categories. • All of the rows in a contingency table is dependant on the results you found in the columns. (See Example)

  3. Problem • 1. Read the following question: • In 2013 Transport Quebec conducted a study connecting the number of car-accidents and text-driving accidents in Quebec. This survey of 5000 respondents found there were 950 people texting while driving. Of those people who text only 20% driving will have a car accident. In the survey, the total amount of car accidents in 2013 is 250 accidents. What is the probability of car accident in 2013? What is the probability of car accidents given the person texting? What is the probability of texting given they have an accident?

  4. Problem • 2. Create a chart that has the variables inside - The two variables are Accidents and Text *Does not Matter what Order it is in*

  5. Problem • 3. Once the variables are place inside you can now place results inside the table. • We know there is 5000 respondents. 950 people text while driving. Of 950 people who text 20% have accident.(.20 x 950) • We also know there is 250 accidents in 2013.

  6. Problem • 4. Once we wrote down the variables and all the numbers inside the variables that we know. we are able to find the missing numbers by either using subtraction or addition. • 5. When all the numbers are complete make sure and check if all the results link to the total amount of respondents. (5000) • 6. When all the numbers are equal to the same amount of respondents, we then could answer the questions

  7. Problem - What is the probability of car accident in 2013? • Since there is no given set the bottom number is total respondents (5000). We then look total amount of accident in a year (250) • ANS: 250/5000 = 5% • What is the probability of car accidents given the person text? • Since now we are given a set of car accidents and texting we need to find total amount of texting and driving accidents (Which is 190) we must determine the total amount of texting while driving (which is 950.) • ANS: 190/950 = 20%

  8. Problem • What is the probability of texting given they have an accident? • Once again we have a given set which is the total amount of car accidents (250) Since we need to find the total car accident (190). • ANS: 190/250 = 76%

  9. Try it your own! • 300 St Thomas High School Grads of 2013 conducted a study were people graduated or not by going to tutorials frequently. The amount of students that went to tutorials was 125. Of those 125 students only 10 did not graduate from High school. In the total population of the entire grade 30% did not graduate and did not go to tutorials. What is the probability of • Graduate? • Not Graduate? • Graduation given that the student went to tutorials? • Went to tutorials given that the student graduated?

  10. Try it your own! • P (Graduation)= 200/300 • P (Not Graduated)= 100/300 • P Graduation given that the student went to tutorials= 115/125 • P Went to tutorials given that the student graduated= 115/200

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