Question

Rh-positive blood appears in 85% of the white population in the united states. Suppose 6 people are sampled at random from that population and answer the following.What is the probability that no more than 5 out of 6 would have RH-positive blood.

*Please explain in depth how you got this answer, and if you used a TI-84 please tell what buttons you used*

Answer 1

We have given p = 0.85 ,  n = 6 and x = 5

This problem is of Binomial distribution.

We have asked to find the probability that no more than 5 out of 6 would have RH-positive blood. That is P(x 5 )

We know that P( x 5 ) = P(x = 0) + P(x = 1) + P(x = 2) + P(x = 3) + P(x = 4) + P(x = 5)

We can find this probability in Ti-84 calculator.

Please follow the commands-

1) Press 2ND ------> VARS

2) select B: binomcdf(

3) After selecting  B: binomcdf( enter the values of n , p and x in order.

so we get B: binomcdf(6 , 0.85 , 5 ) and hit the Enter key it will give you the answer 0.6229 (Rounded to 4 decimal places)

Hence the probability that no more than 5 out of 6 would have RH-positive blood is 0.6229 (Rounded to 4 decimal places)

Hope this will help you. Thank you :)