Exercise 5 Page 370

When calculating the experimental probability, we are comparing the number of times the event occurs to the number of times the experiment is done. P=Times the Event Occurs/Times the Experiment Is Done We know that Kelly flips a coin 20 times. This means that number of times the experiment is done is 20. Out of these she flips heads 11 times, which is the number of times the event occurs. Now we have enough information to calculate P(heads).

P=Times the Evnent Occurs/Times the Experiment is Done

SubstituteValues

Substitute values

P(heads)=11/20

ExpandFrac

a/b=a * 5/b * 5

P(heads)=55/100

WritePercent

Convert to percent

P(heads) = 55 %

The experimental probability that a coin will land heads up is 55 %.