I don't understand the following:

Question 9: Suppose thatxhas a binomial distribution withn= 200 andp= 0.43.(Round np and n(1-p) answers to 2 decimal places. Round youranswers to 4 decimal places. Round z values to 2 decimal places. Round the intermediate value () to 4 decimal places.)

(a)Show that the normal approximation to the binomial can appropriately be used to calculate probabilities aboutx.

My answer:

np = 86

n(1-p) = 114

(b)Make continuity corrections for each of the following, and then use the normal approximation to the binomial to find each probability:

1. P(x=80) --> My answer: On my first attempt I got 0.0390 and my second attempt I got -0.6090. Both are wrong.
2. P(x<=97) --> My answer: 0.9495
3. P(x<74) --> My answer:0.0367
4. P(x>=103) --> My answer: 0.0091
5. P(x>104) --> My answer: 0.0041

Question 23: In order to gain additional information about respondents, some marketing researchers have used ultraviolet ink to pre-code questionnaires that promise confidentiality to respondents. Of 201 randomly selected marketing researchers who participated in an actual survey, 174 said that they disapprove of this practice. Suppose that, before the survey was taken, a marketing manager claimed that at least 83 percent of all marketing researchers would disapprove of the practice.

(a)Assuming that the manager's claim is correct, calculate the probability that 174 or fewer of 201 randomly selected marketing researchers would disapprove of the practice. Use the normal approximation to the binomial.(Round z value to 2 decimal places. Round your answer to 5 decimal places.)

My answer: On my first attempt I got 0.91150 and on my second attempt I got 0.0885. Both are wrong.