# Normal Approximation questions. Finding p?

#### devimon

##### New Member
1) An ESP test involves five shapes (star, square, circle, wave, cross) on cards. We record 1000 attempts. (a) What is the probability that a subject without ESP will be successful in at least 24% of the attempts?(b) The researcher considers evidence of ESP to a proportion of successes so large that there is only probability 0.01 that a subject could do this well or better by guessing. What proportion of successes must a subject have to meet this standard?

n= 1000
p= .20
Why is p = .20 and could you show me how to get to this answer?

2)A massive rocket with 3000 computer chips in its control systems is engineered so that the rocket will work as designed even if 60 chips fail. The chip manufacturer can only guarantee that individual chips will fail at random no more than one and a half percent of the time. Estimate the likelihood that the rocket will fail.

n= 3000
p=0.015
Why is p = 0.015 and could you show me how to get to this answer please?

Thanks and all help is appreciated!