**Answers Normal distribution**

**Exercises**

1. The mean of one entrance exam was 60 and the standard deviation was 12. The results followed the normal distribution.

a) What was the score required for selection if 50% of the candidate was selected.

b) What was the score required for selection if 30% of the candidate was selected.

c) How many scored more than 65 points in the tests

**Answers: a) 60 b) 54 c) 34%**

2. Simo-Elmeri was late for school every day. His time of delay followed the normal distribution. The mean was five minutes and the standard deviation was 2 minutes.

a) In what probability was Simo-Elmeri more than seven minutes late?

b) What is the probability that Simo-Elmeri was less than four minutes late?

c) In what probability was Simo-Elmeri more than four but less than seven minutes late

**Answers: a) 16% b) 31% c) 53%**

3. The dice are rolled 810 times. What is the probability of getting 410 to 420 even numbers?

**Answer: About 24%**

4. It is known that 85% of the 385 guests invited to the party will arrive. The party has 333 seats. In what probability are the seats sufficient?

**Answer: This is a binomial experiment and the normal distribution approximation gives an answer of 81%**