Question

Finding Binomial Probabilities with Ti183 calculator and using format of npq

Consider 10 coin flips :

a)P(exactly 5 heads) =

b)P(exactly 2 heads) =

c)P(more than 7 heads) =

Answer 1

If a coin is tossed ,the probability that getting a head is 0.5

We are given that 10 coins are tossed , so we have n = 10 and p = 0.5

Let x be the number of heads

We use function binompdf(n,p,x) and binomcdf(n,p,x) in TI-83 to find the binomial probability.

Press 2ND key ---> VARS key ---> Select binompdf(n,p,x) or binomcdf(n,p,x)

  

a) P( x = 5 )

To find probability of exact number we use binompdf()

P( x = 5 ) = 0.2461

b) P( x = 2 )

P( x = 2 ) = 0.0439

c) P( x > 7 ) = 1 - P( x ≤ 7 )

To find the sum of probabilities from 0 to 7 we use binomcdf()

P( x ≤ 7 ) = 0.9453

P( x > 7 ) = 1 - P( x ≤ 7 ) = 1 - 0.9453

P( x > 7 ) = 0.0547