Solutions to exercises

1. Solutions to exercises May 8-10, 2006 Iowa State University, Ames – USA Jean-Louis Laffont Kirk Remund

2. Qualitative testing plans – Exercise 1 “I strictly do not want to have any GM seeds in my conventional seed lots” 1. Is this possible to check? If yes how?, if no why? 2. Try to find ad hoc testing plans with Seedcalc LQL=1% beta=approx. 5% LQL=1% beta=approx. 20% LQL=1 per 1000 beta=approx. 5% LQL=1 per 1000 beta=approx. 20% LQL=1 per 10000 beta=approx. 5% LQL=1 per 10000 beta=approx. 20% 3. Choose 2 LQL values, ie levels you wish to reject often and two beta risks (how often you reject this level) => 4 different cases Try to find ad hoc testing plans with Seedcalc ISTA Statistics Committee

3. Qualitative testing plans – Exercise 11. is this possible to check? If yes how?, if no why? • We would have to check each individual seed • Color, or specific fluorescence introduced on purpose, …able to see easily and cheap… • If we look at a few seeds, • we can know, there is presence, if we find some GM seeds, • but we can not tell “there are no GM Seeds” if we did not find any on few seeds • We can look until we find one,…. and reject; or find none =>We must look at as much seeds as needed to have a “good idea”, Option1 = we wish to rarely accept a lot with a given % of presence, Accept=0 LQL= this Low Quality Level Beta= how often we will accept a lot which in fact had this LQL Option2 = we define how many seeds we can look at (time, money…) and see the corresponding risk ISTA Statistics Committee

4. Qualitative testing plans – Exercise 12. Try to find ad hoc testing plans with Seedcalc Find Plan with accept=0 ,LQL=1%, beta=5% A possible answer 2 pools of 150 seeds ISTA Statistics Committee

5. How to get an answer: 1) Type LQL 1% 2) Select a convenient number of seeds per pool 3) Click find plan with zero tolerance ISTA Statistics Committee

6. keep LQL 1%, but accept a greater beta risk, ie 20% instead of 5% For instance, change seeds per pool (from 150 going down) until beta=20% approx 2 pools of 80 seeds ISTA Statistics Committee

7. Find Plan with accept=0, LQL=0.1%, beta=5% 10 pools of 300 seeds 3 pools of 1000 seeds 1 pool of 3000 seeds ISTA Statistics Committee

8. keep LQL 0,1%, but accept a greater beta risk ie 20% instead of 5% For instance, keep 10 pools and decrease nb of seeds per pool 10 pools of 160 seeds (instead of 300 seeds for beta= 5%) ISTA Statistics Committee

9. Find Plan with accept=0, LQL=0.01%, beta=5% 100 pools of 300 seeds ISTA Statistics Committee

10. keep LQL 0,01%, but accept a greater beta risk ie 20% instead of 5% For instance, choose 50 pools as a maximum • 50 pools • 2) Change # of seeds per pool, until beta is approx 20% 50 pools of 320 seeds ISTA Statistics Committee

11. 3. Choose 2 LQL values, ie levels you wish to reject often and two beta risks (how often you reject this level) => 4 casestry to find ad hoc testing plans with seedcalc Zero tolerance Your aim An appropriate answer: LQL1= beta1= =>nb pools: nb seeds per pool: LQL1= beta2= =>nb pools: nb seeds per pool: LQL2= beta1= =>nb pools: nb seeds per pool: LQL2= beta2==>nb pools: nb seeds per pool: ISTA Statistics Committee

12. Pool size set up to 100 Qualitative testing plans – Exercise 2 1. “Xyz” is ready to pay for passing seed lots tested to the following criteria: AQL 0.3% at alpha=5% and LQL 1.5% at beta=5%, what shall I do? ISTA Statistics Committee

13. Qualitative testing plans – Exercise 2 2. Find different possibilities for the following objective:AQL= 0.5% LQL=1% alpha=5% beta=5% Accept if # of deviants does not exceed • 300 seeds/pool 39 pools 34 11700 seeds • 250 39 32 9750 seeds • 200 36 27 7200 seeds • 100 50 25 5000 seeds • 50 78 23 3900 seeds ISTA Statistics Committee

14. 1. Is the testing plan appropriate? NO Quantitative testing plans ISTA Statistics Committee

15. Quantitative testing plans ISTA Statistics Committee

16. Getting an estimate of % of GM - Exercise 1 ISTA Statistics Committee

17. Getting an estimate of % of GM - Exercise 2 ISTA Statistics Committee

18. Getting an estimate of % of GM - Exercise 3 ISTA Statistics Committee

19. Getting an estimate of % of GM - Exercise 3 ISTA Statistics Committee