Market Sizing案例.doc

Market Sizing案例解答：
题目一：请估算中国一年生产的高尔夫球数目
解答：
高尔夫球数目=50 Tier One or Two City * 20 Golf Courts * 300 Days *
Golf Balls Used Times Everyday * Depreciation Rate
Golf Balls Used Times Everyday = (200meters*200meters)/(50 meters*50meters)*
6 times per Hours * 8 Hours
其中(200meters*200meters/50 meters*meters) 为People Capacity
Depreciaiton Rate=1/20，即使用20次损坏或丢失
答案约为1000万个

题目二：请估算北京的加油站数目
解答：
北京的加油站数目=北京的汽车数目*每天加油的次数/每个加油站一天的服务数目
北京的汽车数目=北京人口（=2000万）*20-50岁人口比例（=1/2）*月收入大于5000比例
（1/10）/私车所占比例(=50%)
每天加油的次数=1/每隔多少天加一次油（=10天）
每个加油站一天的服务数目=12Hours*60Minutes/10Minutes*3个加油口
答案约为1000个

题目三：请估算此时此刻中国大陆上空的飞机数目
解答：
中国大陆上空的飞机数目=中国飞机的数目*一架飞机在空中的概率
中国飞机的数目=50 Tier One or Two City * 机场每天吞吐量（即起飞降落数目）
/ 一架飞机一天的起降数目
假设此时此刻在白天，则：
一架飞机在空中的概率 = 飞行时间 /（飞行时间+整修时间）= 2/3
机场每天吞吐量（即起飞降落数目）= 一分钟的起降数（=20分钟起降/20个跑道）* 12H
ours * 60Minutes
一架飞机一天的起降数目 = 二到三个航班*2=5（包含国际航班影响的平均值）
答案约为1万架
During your case interview, you may be asked to make estimates or solve a problem. You'll find two examples below that will help you think through the process of arriving at reasonable estimates. The third question is a brainteaser — a reminder to think creatively when tackling any case interview problem.

Q: How many pay phones are there on the island of Manhattan?

A: A logical place to begin your analysis might be to ballpark the number of pay phones on Manhattan street corners. If you think of New York City as a grid of streets, you might guess it is about 300 streets long (north to south) by ten streets wide (east to west), so it has approximately 3,000 intersections. You might then assume there is one pay phone for every two intersections, for a total of about 1,500 pay phones.

If you’re feeling really creative, you might subtract the number of intersections that are “invalidated because they fall in the area of Central Park. Say Central Park is ten blocks long by two blocks wide, or 20 intersections. Using your one-pay-phone-for-every-two-intersections assumption, you would want to subtract ten pay phones from the original 1,500.

You might then add to the 1,490 the number of pay phones that might be found in restaurants, hotels, schools, hospitals, and office-building lobbies.

Q: How many hotel-sized bottles of shampoo and conditioner are produced each year around the world?

A: You might begin by assuming that hotel-sized bottles are produced for two purposes only:

1. To supply hotels and upscale motels
2. To provide samples for gift packs, salons, and so on

You would then want to start by estimating the number of hotels and motels around the world that offer the products to their guests. One way of estimating the number of hotels is to assume that hotels are found predominantly in major cities and resorts. Figure that there are 2,000 major cities and resorts around the world, an average of ten for each of the world’s approximately 200 countries. Assume that each city averages 20 hotels that offer bottled hair products to their guests Multiplying 20 by 2,000 gives you 40,000 hotels around the world that require shampoo and/or conditioner for their guests.

To understand how many bottles of shampoo and conditioner the 40,000 hotels require, you now need to estimate the total number of uses each hotel on average represents. You can arrive at that number through the following calculation: assume that there are 100 rooms in each hotel, and that those rooms are occupied 50 percent of the time. Multiplying 40,000 by 100 by 0.5 by 365 (don’t forget the number of days in the year!) gives you approximately 750 million.

However, it is probably reasonable to assume that a guest staying for longer than a day will not use a whole shampoo bottle every day. If you assume that an average of one shampoo bottle is used for every two occupied days in a given room, you can now divide your 750 million estimate in half to 375 million. To get to the number of bottles of conditioner, estimate a ratio between the use of shampoo and the use of conditioner. Since many of us do not condition every time we shampoo, you might assume that the ratio is 2:1. Dividing 375 million in half gives you approximately 190 million. Your conclusion would then be that 375 million bottles of shampoo and 190 million bottles of conditioner are required for hotel use every year.

To estimate the total market size, you can probably make things easy on yourself by assuming that the number produced for sample purposes is a small percentage of the total, say ten percent. Combining your two markets would give you approximately 400 million bottles of shampoo and 210 million bottles of conditioner.

Finally, you might want to “reality check” your total figure. Assuming 610 million bottles are produced and sold each year at an average price of 25 cents each, the worldwide market for miniature bottles of shampoo and conditioner is about $150 million. Does that sound reasonable?

Q: You are in a room with three light switches, each of which controls one of three light bulbs in the next room. Your task is to determine which switch controls which bulb. All lights are off. Your constraints are: you may flick only two switches and you may enter the room with the light bulbs only once. How would you set about determining which switch controls which bulb?

A: To solve this riddle you must do some out-of-the-box thinking. The best way to determine which light bulb is which is to flick one switch on, wait for five minutes and flick it off. Then flick one of the remaining two switches on and leave the other off. When you enter the room with the bulbs, you can determine which switch controls which of the two lights that are off by feeling to see which of the bulbs is hot (from having burned for five minutes).

Other creative solutions involve pushing the constraints of the game. You might ask if the room you’re in has a phone, so you could call somebody to help you. You might ask if the rooms have a connecting window. You might assume you can leave the first room a number of times, and therefore go out, buy a drill, and bore a hole through the wall so you can see which light bulb is connected to which switch. Or, you might buy a mirror and place it strategically outside the door to guide you.

Remember, you are limited only by your imagination.
During your case interview, you may be asked to make estimates or solve a problem. You'll find two examples below that will help you think through the process of arriving at reasonable estimates. The third question is a brainteaser — a reminder to think creatively when tackling any case interview problem.
Q: 上海有多少个加油站？
A:
可以从supplier的角度来考虑这个问题，我只要知道多少辆车需要一个加油站，然后知道上海汽车的保有量，就可以得出上海有多少个加油站。
A: 截止到2003年底，上海汽车保有量大概有73万辆。
A: 要得出多少辆车需要一个加油站，可以这样算:
平均一个加油站从早上6:00营业到晚上12:00，工作18个小时，假设有4个油泵，每次为汽车加油平均为5分钟，这样就可以算出一天每个加油站大致为多少辆车加油。
18*60*4/5=860辆。

然后用730000/860 得出850个加油站
截至目前，上海机动车保有量达到200多万量
i believe the answer of 850 is just the right answer for the extreme situation, from the realistic perspective, we have to consider the unoccupied rate for all gas fefillers, which will based on the specific shanghai-based market features.

Q: How many pay phones are there on the island of Manhattan?

A: A logical place to begin your analysis might be to ballpark the number of pay phones on Manhattan street corners. If you think of New York City as a grid of streets, you might guess it is about 300 streets long (north to south) by ten streets wide east to west), so it has approximately 3,000 intersections. You might then assume there is one pay phone for every two intersections, for a total of about 1,500 pay phones.

If you’re feeling really creative, you might subtract the number of intersections that are “invalidated” because they fall in the area of Central Park. Say Central Park is ten blocks long by two blocks wide, or 20 intersections. Using your one-pay-phone-for-every-two-intersections assumption, you would want to subtract ten pay phones from the original 1,500.

You might then add to the 1,490 the number of pay phones that might be found in restaurants, hotels, schools, hospitals, and office-building lobbies.

Q: How many hotel-sized bottles of shampoo and conditioner are produced each year around the world?

A: You might begin by assuming that hotel-sized bottles are produced for two purposes only:

1. To supply hotels and upscale motels
2. To provide samples for gift packs, salons, and so on

You would then want to start by estimating the number of hotels and motels around the world that offer the products to their guests. One way of estimating the number of hotels is to assume that hotels are found predominantly in major cities and resorts. Figure that there are 2,000 major cities and resorts around the world, an average of ten for each of the world’s approximately 200 countries. Assume that each city averages 20 hotels that offer bottled hair products to their guests. Multiplying 20 by 2,000 gives you 40,000 hotels around the world that require shampoo and/or conditioner for their guests.

To understand how many bottles of shampoo and conditioner the 40,000 hotels require, you now need to estimate the total number of uses each hotel on average represents. You can arrive at that number through the following calculation: assume that there are 100 rooms in each hotel, and that those rooms are occupied 50 percent of the time. Multiplying 40,000 by 100 by 0.5 by 365 (don’t forget the number of days in the year!) gives you approximately 750 million.

However, it is probably reasonable to assume that a guest staying for longer than a day will not use a whole shampoo bottle every day. If you assume that an average of one shampoo bottle is used for every two occupied days in a given room, you can now divide your 750 million estimate in half to 375 million. To get to the number of bottles of conditioner, estimate a ratio between the use of shampoo and the use of conditioner. Since many of us do not condition every time we shampoo, you might assume that the ratio is 2:1. Dividing 375 million in half gives you approximately 190 million. Your conclusion would then be that 375 million bottles of shampoo and 190 million bottles of conditioner are required for hotel use every year.

To estimate the total market size, you can probably make things easy on yourself by assuming that the number produced for sample purposes is a small percentage of the total, say ten percent. Combining your two markets would give you approximately 400 million bottles of shampoo and 210 million bottles of conditioner.

Finally, you might want to “reality check” your total figure. Assuming 610 million bottles are produced and sold each year at an average price of 25 cents each, the worldwide market for miniature bottles of shampoo and conditioner is about $150 million. Does that sound reasonable?

Q: You are in a room with three light switches, each of which controls one of three light bulbs in the next room. Your task is to determine which switch controls which bulb. All lights are off. Your constraints are: you may flick only two switches and you may enter the room with the light bulbs only once. How would you set about determining which switch controls which bulb?

A: To solve this riddle you must do some out-of-the-box thinking. The best way to determine which light bulb is which is to flick one switch on, wait for five minutes and flick it off. Then flick one of the remaining two switches on and leave the other off. When you enter the room with the bulbs, you can determine which switch controls which of the two lights that are off by feeling to see which of the bulbs is hot (from having burned for five minutes).

Other creative solutions involve pushing the constraints of the game. You might ask if the room you’re in has a phone, so you could call somebody to help you. You might ask if the rooms have a connecting window. You might assume you can leave the first room a number of times, and therefore go out, buy a drill, and bore a hole through the wall so you can see which light bulb is connected to which switch. Or, you might buy a mirror and place it strategically outside the door to guide you.