Question

Assume that on a standardized test of 100 questions, a person has a probability of 80% of answering any particular question correctly. Find the probability of answering between 72 and 82 questions, inclusive. (Assume independence, and round your answer to four decimal places.) P(72 ≤ X ≤ 82) =

Answer 1

Here we can use the normal approximation to the binomial distribution

Condition to check:

with the number of trials: n= 100 question

The probability of success(probability of answering any particular question correctly) : p =0.80

Mean :

standard deviation:

To Find the probability of answering between 72 and 82 questions, inclusive we need to find the corresponding Z score

For 72

For 80

the probability of answering between 72 and 82 questions=