1. Warmup
Juan bought a used car for $8,600. It has a book value of $8,200.
a) How much sales tax would he pay if the rate is 6%?
b) How much ad valorum tax would he pay if the rate is 7.25%?Sales Tax – percent of purchase price
2. A classified ad costs $22 for the first 3 lines and $4.50 for each additional line
Write a piecemeal function to represent the cost of the ad
Find the cost of a 10-line ad.

2. OBJECTIVES 5-2 BUY OR SELL A CAR
Banking
9/17/2018
5-2 BUY OR SELL A CAR
OBJECTIVES
Compute mean, median, mode, range, quartiles, and interquartile range.
Chapter 1

3. How do you determine a fair price
for a vehicle?
Internet (Kelley Blue Book and Edmunds)
Visit dealers
Look at prices of similar cars in ads
Make sure you take mileage and condition into account

4. Finding the mean (or average) price of similar cars is one method of determining a fair price
Example 1
Jason wants to sell his Ford SUV. He compiles these prices from the Internet for cars similar to his: $11,000, $9,900, $12,100, $10,500, and $9,000. What is a reasonable price for Jason to consider for his SUV?

5. Example 2
Maxine compiled a list of these car prices: $7,500, $6,500, $5,750, $4,900, $6,250, and $4,200. Find the mean of the prices.

6. If one or more of the prices is very different from the others, the median is a better measure of a representative price
Example 3
Dory is looking for a classic 1967 Firebird. She finds these prices on the Internet: $18,000, $77,000, $22,000, $21,200, $19,000, $17,500, and $22,500. She computes the mean as $28, This number doesn’t seem to be a good representative of the data. How can she find a better representation?

7. Example 4
Find the mean and median of the following prices for a used car extended warranty: $1,200, $1,650, $1,500, $2,000, $1,400, $1,850, and $1,600. Is the data skewed?

8. EXAMPLE 5
Find the median of the following used car prices: $6,700, $5,800, $9,100, $8,650, $7,700, and $7,800.

9. The range measures how spread out the data is
The range measures how spread out the data is. The range is the difference between the largest and smallest value
EXAMPLE 6
Prices found online for the same GPS navigation system are $295, $345, $199, $225, and $200. Find the range of the GPS prices.

10. EXAMPLE 7
Find the range of the classic Firebird prices in Example 3.

11. The quartiles also measure how spread out the data is
The quartiles also measure how spread out the data is. The quartiles divide the data into groups that each contain 25% of the data.
Q2 is the same as the median
Q1 is the median of the numbers below the median
Q3 is the median of the numbers above the median
IQR (Interquartile range) is the difference between Q3 and Q1

12. Tire pressure is measured in psi—pounds per square inch.
EXAMPLE 8
Find the quartiles and IQR for the tire pressures of cars at an auto clinic.
15, 17, 21, 25, 31, 32, 32, 32, 34
Tire pressure is measured in psi—pounds per square inch.

13. Find the quartiles and IQR for these tire prices:
Example 9
Find the quartiles and IQR for these tire prices:
$45, $88, $109, $129, $146, $189, $202, $218, and $545

14. The mode is the value that occurs the most
Example 10
Find the mode of the tire pressures from Example 8.
15, 17, 21, 25, 31, 32, 32, 32, 34