Name_________________________

STUDENT INSTRUCTION AND ANSWER SHEET

Activity 2: Concept Introduction-Making Complex Estimates


There are many instances in science where estimation is much more useful and efficient than counting. In particular, estimation techniques are important when analyzing a system for which counting is not actually possible. Complete the following estimation task.

PREDICTION: How many females in the 9th grade with long hair are scheduled to be at lunch between 12:15 and 12:30 and are eating in the cafeteria and having french-fries with ketchup? __________________

TASK: To check your prediction, complete the following table by estimating the:

Variable
Estimated Value
Notes
n - total number of students in your school
   
ff- fraction of females in your school
   
ff,9 - fraction of those females in 9th grade    
ff,9,L - fraction of those females in 9th grade with long hair    
ff,9,L,t - fraction of those females in 9th grade with long hair at lunch between 12:15 and 12:30    
ff,9,L,t,c - fraction of those females in 9th grade with long hair at lunch between 12:15 and 12:30 in the cafeteria    
ff,9,L,t,c,FF - fraction of those females in 9th grade with long hair at lunch between 12:15 and 12:30 in the cafeteria eating french-fries    
ff,9,L,t,c,FF,k - fraction of those females in 9th grade with long hair at lunch between 12:15 and 12:30 in the cafeteria eating french-fries with ketchup    
F - Fraction Of Total Population
(the product of all the fractions)
   
T - Number of People at Your School Meeting The Criteria (product of fraction of total population F, and the total school population, n)    

CLASS AVERAGE, Tavg

   

Reflection Questions about the Lunchroom Equation

T = n x ( ff x ff,9 x ff,9,L x ff,9,L,t x ff,9,L,t,c x ff,9,L,t,c,FF x ff,9,L,t,c,FF,k ) = n x (F)


A. What value of T did you determine and how did it compare with the class average?


B. Give specific reasons why your value was different than the class average.

 

 


C. Predict how the calculation will change if you observe males instead of females. Check your prediction by performing the necessary calculation.

 

 

 


D. Explain how the value of T would be different if you changed your definition of long hair. Provide an example calculation with your written explanation.

 

 

 

 


E. Suppose that you were making this estimate for an all-female school where lunch is served from 12 to 1 pm. How would your estimate change? Why?