Used Car Prices Coursework

Data Investigation USED CAR PRICES The Problem What factors affect the price of used cars? You must produce a report to answer this question from car data. Your report should use maths to show how factors such as age affect the price of a car. The Problem What factors affect the price of used cars? Age Condition Make and Model Desirability and Demand Here are 100 used cars What kind of cars are for sale? How could I show information about the cars for sale? Colour Hypothesis: what do I think the most/least popular colours are? To draw a BAR chart from the data sheet you first need a Frequency Table: Colour Red White Tally II III Frequency 2 3 Do you need to list every colour? Bar Chart Colour of Cars Colour Frequency 30 25 Black Blue** Green* Grey/Silver Red*** 12 23 9 18 26 Frequency 20 15 10 5 0 White Gold Purple Total 10 1 1 100 G re en * R ed ** * lu e* * er G re y/ S B W hi te B Colour *includes tourmaline **includes marine & cuirass ***includes burgundy/aubergine/nightfire Analysis: what does the chart show? P ur pl e G ol d la ck ilv Make Hypothesis: what do I think the most/least popular makes are? To draw a PIE chart from the data sheet you first need a Frequency Table: Make Ford Other Tally II III Frequency 2 3 Do you need to list every make? Pie Chart There are 100 cars so each car is worth 360 ÷ 100 = 3.6º Car Make Ford Citreon Make Ford Citreon Daewoo Fiat Mercedes Nissan Peugot Renault Rover Vauxhall Volkswagen Other Total Frequency 16 3 3 10 3 6 5 5 12 13 7 17 100 Daew oo Fiat Mercedes Nissan Peugot Renault Rover Vauxhall Volksw agen Other Explanation: when is it better to use a bar or pie chart? Hypothesis: I think that older cars are cheaper Test the hypothesis with a scatter graph: Do I need to use all 100 cars? Use SAMPLING Sampling All 100 cars are the POPULATION Sampling means selecting an unbiased group of cars Sampling All 100 cars are the POPULATION Sampling means selecting an unbiased group of cars RANDOM Sampling Cars are picked using a random number list or generator On a calc. Press SHIFT RAN# = then × by 100 RANDOM Sampling Cars are picked using a random number list or generator On a calc. Press SHIFT RAN# = then × by 100 Example 0.508 × 100 = 50.8 = 50th car SYSTEMATIC Sampling Cars are selected evenly Example If I want 20 cars for my sample then I pick every... 100 ÷ 20 = 5 …5th car SYSTEMATIC Sampling Cars are selected evenly Example If I want 20 cars for my sample then I pick every... 100 ÷ 20 = 5 …5th car Hypothesis: I think that older cars are cheaper Choose your sampling method and tabulate the information to test this hypothesis Car Age (years) 3 4 5 … Used price 5th 10th 15th … £7995 £7499 £3995 … Hypothesis: I think that older cars are cheaper Plot age and price on a Scatter Graph Car Used Price vs Car Age 12 10 Used Price (£s) 8 6 4 2 0 0 2000 4000 6000 8000 10000 12000 14000 16000 Age (years) Hypothesis: I think that older cars are cheaper What does the scatter graph show? Should I disregard certain data? How can I use the line of best fit – is it accurate? should it be straight? What conclusions can I draw? What predictions can I make? Used Car Prices Checklist: Introduction page: problem and ideas Analysis of used car data sheet: hypothesis, tally charts, 1 bar chart and 1 pie chart, explanation Sampling: how sampled Comparison of age/price, other/price by scatter graph. Explanation of graphs (relationship, ignored points), line of best fit Depreciation: value lost over time Hypothesis How do you think depreciation affects used car price? Car Price # New (£) 1 2 16000 Price Used (£) 7999 % Value Lost (depreciation) 50% Is depreciation different? Why? Depreciation: value lost over time How is depreciation calculated? price new – price used = value lost Car 1: 16000 – 7999 = £8001 value lost ÷ price new x 100 Car 1: 8001 ÷ 16000 × 100 = 50% In its’ first year car 1 lost 50% of its’ value Depreciation: value lost over time Construct a scatter graph for a sample of cars % Depreciation Age Depreciation: value lost over time How does depreciation affect used car price? Write a summary stating what you have found out Compare your results with your hypothesis