Math 11 - Lesson 4.3B: Measure central tendency & dispersion

The average monthly salary of 12 workers and 3 managers in a factory was Rs.600. When one of the managers whose salary was Rs. 720, was replaced with a new manager, the average salary of the team went down to Rs. 580. What is the salary of the new manager?

• 570

• 420

• 690

• 640

• none of those

The average age of a group of 12 students is 20 years. If 4 more students join the group, the average age increases by 1 year. The average age of the new students is ____

• 25

• 26

• 28

• 22

• none of those

The average weight of a class of 24 students is 36 kg. When the weight of the teacher is also included, the average weight increases by 1 kg. What is the weight of the teacher?

• 60 kg

• 61 kg

• 37 kg

• None of the above

• 39 kg

The average age of a family of 5 members is 20 years. If the age of the youngest member is 10 years, what was the average age of the family just a day before the birth of the youngest member?

• 13.5

• 14

• 15

• 12.5

• none of those

A class had 9 students. In one test, the class average was 61. One student's paper was scored incorrectly, and the resulting score was raised 18 points. What is the corrected class average?

• 70

• 63

• 72

• 78

• none of those

Mrs. Carmendy's class had an average score of an 89. She forgot to add in a student who got a 10% on the test. How will this affect the class average?

• Increase

• Decrease

• Stay the same

• it will both increase and decrease

• none of those

Mrs. Algebra's class has an average grade of 87. Later on she realizes she left out Joe's score. His grade was a 65. The new mean will ,....

• increase

• decrease

• stay the same

• it will both increase and decrease

• none of those

If a number is added to a set that is smaller than the mean. How does this affect the mean?

• increase

• decrease

• stay the same

• it will both increase and decrease

• none of those

If a number is added to a set that is the same as the mean, how does this affect the mean?

• increase

• decrease

• stay the same

• it will both increase and decrease

• none of those

If a number is added to a set that is far away from the mean, how does this affect standard deviation?

• increase

• decrease

• stay the same

• it will both increase and decrease

• none of those