Question

Strawberry Discoloration Problem #1 The following problem is taken from an actual Advanced Placemens Sustistics Examinatioa. Your lask is to generaie a complete, concise statistical response in 10 minules. You will be graded based on the AP rubric and will earn a score of 0-4. After grading, keep this problem in your binder o review before each unit test and for your AP Exam preparacion e department of agriculture at a university was interested in determining whether a preservative was ective in reducing discoloration in frozen strawberries. A sample of 50 ripe strawberries was prepared for ezing. Then the sample was randomly divided into two groups of 25 strawberries each. Each strawberry s placed into a small plastic bag The 25 bags in the control group were sealed. The preservative was added to the 25 bags containing strawberries in the treatment group, and then those bags were sealed. All bags were stored at O'C for a period of 6 months. At the end of this time, after the strawberries were thawed, a technician rated each strawberry's coring: discoloration from 1 to 10, with a low score indicating little discoloration. The dotplots below show the distributions of discoloration rating for the control and treatment groups. i 2 3 4 5 6 789 10 Discoloration Rating P I (a) The standard deviation of the ratings for the control group is 2.141. Explain how this value summarizes variability in the control group. (b) Based on the dotplots, comment on the effectiveness of the preservative in lowering the amount of discoloration in strawberries. (No calculations are necessary.)

Answer 1

(a)

On an average, the deviation of a rating from the mean rating of control group is 2.141

(b)

From the dotplots, it seems that the preservative is effective in lowering the amount of discoloration in strawberries because in control group, the data is skewed left with more bags having higher ratings whereas in treatment group the data is approximately normally distributed with more bags having lower ratings.