CFA考點一：Breakeven Point
精選問答1：
The demand schedule in a perfectly competitive market is given by P=93-1.5Q (for Q≤62)and the long-run cost structure of each company is:
Total cost: 256+2Q+4Q2
Average cost: 256/Q+2+4Q
Marginal cost: 2+8Q
New companies will enter the market at any price greater than:
A 8
B 66
C 81
答案：
B is correct. The long-run competitive equilibrium occurs where MC=AC=P for each company. Equating MC and AC implies 2+8Q=256/Q+2+4Q.
Solving for Q gives Q=8. Equating MC with price gives P=2+8Q=66. Any price above 66 yields an economic profit because P=MC>AC, so new companies will enter the market.
CFA考試解題思路
這題主要考察以下兩個考點，第一個是是盈虧平衡點(breakeven point)。在完全競爭市場上，P=ATC是廠商的盈虧平衡點。而在P>ATC時，利潤會吸引新廠商進入。第二個考點:單個廠商在完全競爭市場上均衡條件下有P =MR =MC=AC;根據(jù)此公式，本題聯(lián)立MC=AC 即可求出答案。
易錯點分析
很多同學都有這樣的疑問：為什么不可以聯(lián)立P=MC或者P=AC直接來求解。那是因為我們算盈虧平衡點時，需要用到單個廠商的需求曲線，而非整個市場的需求曲線。但是題目中給的需求曲線公式卻是整個市場的，因此不可選用。所以本題中均衡條件下的完全競爭市場滿足P=AC，所以可直接用MC=AC來計算此題。本題需要注意區(qū)分單個廠商和整個市場的需求曲線。
CFA考點二：Economies of Scale
精選問答2：
A firm that increases its quantity produced without any change in per-unit cost is experiencing:
A economies of scale
B diseconomies of scale
C constant returns to scale
答案：
C is correct. Output increases in the same proportion as input increases occur at constant returns to scale.
解題思路
題目中說到產(chǎn)量增加，“單位成本”不變，那么它就是指規(guī)模報酬不變。換言之，成本和產(chǎn)量等比例地增加。
易錯點分析
很多同學都選了A。A選項錯在規(guī)模經(jīng)濟下，單位成本是下降的。 如果A選項說“總成本”不變?？偖a(chǎn)出增加，單位成本不變是指規(guī)模經(jīng)濟(如下圖所示)。所以在做類似題目的時候，大家需要看清題目究竟問的是“單位成本”還是總成本。
CFA考點三：Profit Maximum
精選問答3
A profit maximum is least likely to occur when:
A average total cost is minimized
B marginal revenue equals marginal cost
C the difference between total revenue and total cost is maximized
答案：
A is correct. The quantity at which average total cost is minimized does not necessarily correspond to a profit maximum.
解題思路
Profit=TR-TC; ①當兩者之差達到最大值時，說明此時的profit為最大值;②求導方法，TR'-TC'=0時，此時profit達到最大值，即MR=MC
易錯點分析：
這道題不少同學都沒有看清least likely，最后選擇錯誤。選擇A是因為判斷profit大小時，不能單由cost判斷，還要考慮revenue和產(chǎn)量。Cost最低的時候，Revenue和產(chǎn)量可能同時比較小，如此總的Revenue就很低，那么利潤也很低。
CFA考點四：影響LM曲線平移的因素
精選問答4
An increase in the price level would shift the
A IS curve.
B LM curve.
C aggregate demand curve.
答案：
B is correct. The LM curve represents combinations of income and the interest rate at which the demand for real money balances equals the supply. For a given nominal money supply, an increase in the price level implies a decrease in the real money supply. To decrease the demand for real money balances, either the interest must increase or income must decrease. Therefore, at each level of the interest rate, income (= expenditure) must decrease—a leftward shift of the LM curve.
解題思路
影響LM的平移的因素就是比實際貨幣供給。實際貨幣供給=名義貨幣供給/物價水平。因此，物價水平的改變可以影響LM曲線的平移。
易錯點分析
這道題有些同學選擇了C選項。C選項中提及的總需求AD曲線，它的橫坐標就是物價水平P，因此，物價水平的變動只會引起曲線上的點沿著曲線移動，而非曲線的平移。
此外還需注意到，一國總產(chǎn)出可以表示為Y=C+I+G+(X-M)，等式右邊第一項消費C和總產(chǎn)出Y有關，第二項投資I和利率水平r有關。那么剩下來的兩項政府支出G以及凈出口(X-M)便是影響IS曲線平移的因素，和物價水平?jīng)]有關系。
CFA考點五：充分就業(yè)時的產(chǎn)出水平
精選問答5
The full employment, or natural, level of output is best described as:
A the maximum level obtainable with existing resources.
B the level at which all available workers have jobs consistent with their skills.
C a level with a modest, stable pool of unemployed workers transitioning to new jobs.
C is correct. At the full employment, or natural, level of output the economy is operating at an efficient and unconstrained level of production. Companies have enough spare capacity to avoid bottlenecks, and there is a modest, stable pool of unemployed workers (job seekers equal job vacancies) looking for and transitioning into new jobs.
解題思路
充分就業(yè)時仍然會存在一部分失業(yè)，但是這部分失業(yè)是穩(wěn)定溫和的，并且這些失業(yè)工人可以通過培訓實現(xiàn)再就業(yè)。
易錯點分析
這道題會有不少CFA報名考生誤選了A選項。A選項暗含了利用所有勞動力的意思，但是我們說充分就業(yè)的情況下，依然存在結構性失業(yè)以及摩擦性失業(yè)。所以相比較C選項，A選項的說法不夠準確。
CFA考點六：target exchange rate
精選問答6
A country that maintains a target exchange rate is most likely to have which outcome when its inflation rate rises above the level of the inflation rate in the target country?
A. An increase in short-term interest rates.
B. An increase in the domestic money supply.
C. An increase in its foreign currency reserves.
答案：
A is correct. Interest rates are expected to rise to protect the exchange rate target.
解題思路
如果A國盯住B國的匯率，那么A國通脹上漲會導致A國的貨幣貶值。為了阻止A國貨幣的貶值，A國可以實施一個緊縮的貨幣政策，提升利率水平，吸引外資流入，穩(wěn)定匯率水平。所以A選項正確。
易錯點分析：
這道題有不少同學會在C選項上猶豫。如果A國增加自己的外匯儲備，它相當于與賣出本國的貨幣，買進外國的貨幣。那么大量的本國貨幣投放如市場，類似于實施了一個擴張的貨幣政策。這會導致A國匯率降低而不是升高。
此外，B選項增加貨幣供給是一個擴張的貨幣政策，它會導致利率下降，幣值下跌，也不入選。
CFA考點七：Trade restrictions
精選問答7
A large country can:
A benefit by imposing a tariff.
B benefit with an export subsidy.
C not benefit from any trade restriction.
答案：
A is correct.
By definition, a large country is big enough to affect the world price of its imports and exports. A large country can benefit by imposing a tariff if its terms of trade improve by enough to outweigh the welfare loss arising from inefficient allocation of resources.
解題思路
在國際貿易領域，大國對一款產(chǎn)品的需求量占比過高，會對該類產(chǎn)品的世界價格水平產(chǎn)生影響。大國設置關稅后會大幅降低全球范圍對于該種商品的需求量，從而導致該種商品世界價格的下降，大國的消費者因此獲利。
易錯點分析
注意到，國際貿易中的大國并不是指該國國土面積比較大，或者指該國的GDP比較高。而是指該國對某種商品的需求量占比非常高。對于這題，有很多CFA報名考生會選C選項。既然A選項入選，C選項就錯誤。對于這個結論，大家可以記憶一下。
CFA考點八：經(jīng)常性賬戶與資本流
精選問答8
Because of a sharp decline in real estate values, the household sector has increased the fraction of disposable income that it saves. If output and investment spending remain unchanged, which of the following is most likely correct?
A A decrease in the government deficit.
B A decrease in net exports and increased capital inflow.
C An increase in net exports and increased capital outflow.
答案：
C is correct. The fundamental relationship among saving, investment, the fiscal balance, and the trade balance is S=I+(G-T)+(X-M). Given the levels of output and investment spending, an increase in saving (reduction in consumption)must be offset by either an increase in the fiscal deficit is not one of the choices, so an increase in net exports and corresponding increase in net capital outflows (increased lending to foreigners and/or increased purchases of assets from foreigners) is the correct response.
這題需要運用S=I+(G-T)+(X-M)這個公式。題中說到房地產(chǎn)的價值下降從而增加儲蓄。當投資(I)不變，根據(jù)該公式我們可以知道儲蓄(S)增加時財政赤字(G-T)和凈出口(X-M)會增加。A選項政府赤字下降顯然是錯誤的，B選項的凈出口下降也是錯誤的，因此選擇C。
易錯點分析
這個公式是由總收入=總支出聯(lián)立得來的。即把C+I+G+X-M=C+S+T轉化一下可得S=I+(G-T)+(X-M)。S為儲蓄;I為投資;(G-T>0)為財政赤字;(X-M)為凈出口。
而此題的capital outflow 表示資本賬戶外流。進出口代表的是經(jīng)常性賬戶，它和資本賬戶是此消彼長的關系。當進出口增加時，貿易盈余所產(chǎn)生的多余外匯就要到國外市場進行投資，所以資本賬戶資金外流，這便是net capital outflows。
經(jīng)濟學的精選問答就到這里啦。
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