Question

Alison is learning how to walk. 50% of the time that she takes a step she falls down. Her older brother wants to design a simulation to find the probability she will fall down 5 out of the next 7 times she tries to take step. Which simulation design has an appropriate device and a correct trial? A) Roll a die letting 1 represent Alison falling and 2-6 represent Alison not falling. Roll the die five times. B) Roll a die letting 1 represent Alison falling and 2-6 represent Alison not falling. Roll the die seven times. C) Let Heads represent Alison falling down and Tails representing Alison not falling down. Flip the coin five times. D) Let Heads represent Alison falling down and Tails representing Alison not falling down. Flip the coin seven times.

Answer 1

Answer:

(D)

Step-by-step explanation:

Simulation   <--> (corresponds to)   Real world  as follows

Flip of coin     <-->    Alison tries to take a step

"Flip the coin 7 times"   <-->   "the next 7 times she tries to take a step"

Heads   <-->   Alison falls down

50% probability of heads    <-->   50% of the time she takes a step she falls

Notice that:

probability of 5 heads in 7 tosses   <-->  probability of 5 falls in 7 steps

so to investigate the probability of Alison falling down 5 out of the next 7 times she tries to take a step, the brother will need to look at the probability of getting 5 heads in 7 tosses in his simulation.