MA 111 Review for Exam 2Exam 2 (given in class on Tuesday, March 2) will cover numbers and quantities, percentand percent change, mean and median, and the introduction to indices.Can you work each homework, worksheet, and quiz problem correctly and quickly, pro-viding explanations and justifications, without looking at the text or your notes?Have you carefully studied the material in the text?You should be familiar with the following key ideas:• Understand the difference between number and quantity.• Know how to convert units (e.g., miles/hour to feet/sec).• Know how to compare quantities with ratios and with percents.• Know how to understand, or make better sense, of very large or very small quantities.• Understand the importance of correct units.• Understand what percent means.• Know what the base of a percent is, and be able to identify the base of a percent incontext.• Be able to find different variables in a percentage calculation (e.g., use the base andthe result to find the percent).• Understand how changes in numbers can be measured by percents (percent change).• Know how to increase or decrease a number by a percentage, and how to reverse thisprocess.• Understand the difference between (1) change, (2) percent change, (3) change in percent(percentage points), and (4) percent change of percent.• Understand the difference between mean and median, and know how to compute themand to solve problems involving these quantities.• Be able to create an index from a collection of data, to figure out the index values fromdata values, and to figure out data values from index values.• Be able to interpret a short passage and analyze the given information about numbers,quantities, percents, p erce nt change, means, medians, and indices.1Practice Problems1. Review the practice problems for Exam #1, and also the problems from Exam #1itself.2. A data set of 10 numbers has mean 40. What is their sum?3. A data set of 8 numbers has mean 50. The data set is enlarged by introducing a 9thnumber, 14. What is the new mean?4. A data set of 5 numbers has mean 88. What is the smallest value of a sixth numberthat can be introduced into the data se t to raise the mean to 90?5. A data set of 11 numbers has median 12. How many numbers in the data set are lessthan 12? How many numbers in the data set are less than or equal to 12? How doyour answers change if you know that all of the numbers in the data set are different?6. Ask a friend to give you two different numbers a and b. Construct a data set withmean a and median b. With mean b and median a.7. Below is a partial table of an index for the cost of a gallon of fuel oil. Fill in the missingnumbers.Year Cost of gallon of oil Cost-of-Oil Index2006 2.4182007 18.882008 26.602009 2.509 20.002010
View Full Document
Unlocking...