Name_________________________

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?