Part 1:

A teacher gives a 20-point test to 12 students. The scores are shown below.

18 17 12 8 8 17 3 7 12 10 20 12

Find the following:

1)Mean

2) Mode(s)

3)Range

4)Quartiles

5) The teacher forgot to add the grade of the 13thstudent, when he did do, the mean of the

class was 12.5. What was the student's grade?

Part 2:

An exam consists of 10 multiple choice questions and each question consists of four choices. There is only one correct answer per question and all the questions must be answered. If each question is worth 10 points, what is the probability that you will get 70% on the exam?

Part 3:

A research is made to construct a 99% confidence interval for the mean time it takes Moroccan boys (12-18 years old) to get a haircut per year. An independent researcher randomly selected 20 boys (12-18 years old) and obtained these data.

3 2 1 3 7 2 9 4 6 6

8 0 5 6 4 2 1 3 4 1

Assume the distribution is normal, construct the confidence interval.

Part 4:

Statistics Spring 2021, IUL

Over 1034 people, there are 840 who are interested to get the Covid-19 vaccine. Give a 96% confidence interval for the proportion of people NOT willing to get the vaccine.