CFA Level I quantitative methods and fixed income practice: cram pack

Formula sheets, the key method steps for every topic and 20 practice problems, with full solutions at the back.

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1Formulas and methods

Time value of money

Future value
FV = PV·(1 + i)n
Present value
PV = FV/(1 + i)n
Several periods per year
i = r/m, N = m·n
Annuity, present value
PV = PMT·[1 − (1 + i)−n]/i
Annuity, future value
FV = PMT·[(1 + i)n − 1]/i

Method

  1. Draw a timeline with every cash flow and its timing.
  2. Match the rate to the period: a monthly rate for monthly payments.
  3. Use FV = PV·(1 + i)ⁿ for single amounts and the annuity formulas for equal payments.
  4. Check the sign and the order of magnitude of the answer.

NPV & IRR

Net present value
NPV = −C0 + Σ CFt/(1 + r)t
Equal cash flows
NPV = −C0 + CF·[1 − (1 + r)−n]/r
Internal rate of return
the r at which NPV = 0
Decision
accept when NPV > 0 (or IRR > required return)

Method

  1. List all cash flows with their year; the investment at year 0 is negative.
  2. Discount each cash flow: CFt/(1 + r)t.
  3. Add them up to get the NPV. Positive means the project earns more than r.
  4. For the IRR, find the rate that makes NPV zero by trial or interpolation.

Bond pricing & yield

Bond price
P = C·(1 − (1 + y)−n)/y + F/(1 + y)n
Semi-annual
C/2, y/2 and 2n periods
Current yield
C/P
Price and yield
yield up → price down

Method

  1. Find the coupon per period and the yield per period.
  2. Price = present value of the coupons (an annuity) + present value of the face value.
  3. For semi-annual coupons use half the coupon, half the yield and twice the periods.
  4. Check: if the yield is above the coupon rate, the price is below face value.

CAPM & WACC

CAPM
re = rf + β·(rm − rf)
WACC
E/V·re + D/V·rd·(1 − T)
Firm value
V = E + D

Descriptive statistics

Mean
x̄ = Σx/n
Sample standard deviation
s = √(Σ(x − x̄)²/(n − 1))
Median
middle value of the sorted data
z-score
z = (x − μ)/σ
Normal distribution
68% within ±1σ, 95% within ±2σ

Probability

Complement
P(not A) = 1 − P(A)
Addition rule
P(A ∪ B) = P(A) + P(B) − P(A ∩ B)
Independent events
P(A ∩ B) = P(A)·P(B)
Conditional probability
P(A|B) = P(A ∩ B)/P(B)
Binomial
P(X = k) = C(n,k)·pk(1 − p)n−k

Normal distribution

z-score
z = (x − μ)/σ
Below x
P(X < x) = Φ(z)
Above x
P(X > x) = 1 − Φ(z)
Between
Φ(z2) − Φ(z1)
Percentile
x = μ + z·σ

Method

  1. Convert the value to a z-score: z = (x − μ)/σ.
  2. Look up Φ(z), the area to the left of z.
  3. For the area to the right use 1 − Φ(z); for an interval subtract the two left areas.
  4. For a percentile, work backwards: find z for the area, then x = μ + z·σ.

Confidence intervals

σ known
x̄ ± z·σ/√n
σ unknown
x̄ ± t·s/√n, df = n − 1
Critical z
90%: 1.645, 95%: 1.96, 99%: 2.576
Sample size
n = (z·σ/E)², rounded up

Method

  1. Decide between z (population σ known) and t (only the sample s, with n − 1 degrees of freedom).
  2. Find the critical value for the confidence level.
  3. Margin of error: E = critical value × standard deviation/√n.
  4. Interval: x̄ ± E.

Hypothesis tests & confidence intervals

z-test for a mean
z = (x̄ − μ0)/(σ/√n)
t-test for a mean
t = (x̄ − μ0)/(s/√n), df = n − 1
Two-sided at 5%
reject H0 if |z| > 1.96
Confidence interval
x̄ ± z·σ/√n

Method

  1. State H₀ and H₁ and decide whether the test is one- or two-sided.
  2. Calculate the test statistic: (x̄ − μ₀)/(σ/√n), or with s and t.
  3. Compare with the critical value, or find the p-value.
  4. Reject H₀ if the statistic is beyond the critical value (p below α), and state the conclusion in words.

Linear regression & correlation

Sums of squares
Sxx = Σ(x − x̄)² = Σx² − (Σx)²/n, Sxy = Σxy − ΣxΣy/n
Slope
b = Sxy/Sxx
Intercept
a = ȳ − b·x̄
Correlation
r = Sxy/√(SxxSyy)
Residual
e = y − ŷ

2Practice problems

1.Time value of moneyMedium
periods0123411 + EAR = ?19.5% / 4

A credit card charges a nominal interest rate of 19.5% per year, compounded quarterly. Find the effective annual rate EAR in percent.

r = 19.5%m = 4
EAR = %
2.Time value of moneyHard
months0123…300€200€200€200FV = ?

You save €200 at the end of every month for 25 years. The account pays 3.6% per year, compounded monthly. How much have you saved at the end? Find FV.

A = €2003.6% / 12N = 300
FV = €
3.NPV & IRRMedium
years0123456−60 00018 00014 50026 00017 50022 50016 500

A project costs €60 000 today and returns €18 000, €14 500, €26 000, €17 500, €22 500, €16 500 at the end of years 1 to 6. The cost of capital is 12%. Assume cash flows arrive evenly through each year. Find the discounted payback period DPB in years.

r = 12%CF0 = −60 000CF1 = 18 000CF2 = 14 500CF3 = 26 000CF4 = 17 500CF5 = 22 500CF6 = 16 500
DPB = years
4.NPV & IRRHard
years0123−50 00033 00018 50023 000

A project costs €50 000 and returns €33 000, €18 500, €23 000 at the end of years 1 to 3. Find its internal rate of return IRR in percent.

CF0 = −50 000CF1 = 33 000CF2 = 18 500CF3 = 23 000
IRR = %
5.Bond pricing & yieldMedium
half-years0123456€10€10€10 + €1 000P = ?

A bond with a face value of €1 000 pays a 2% annual coupon in two half-yearly payments and matures in 3 years. The yield to maturity is 5% per year. Find the price P of the bond.

F = €1 000coupon = 2%YTM = 5%n = 3
P = €
6.Bond pricing & yieldHard

A bond trades at €940 with a yield to maturity of 3% (annual compounding) and a Macaulay duration of 6.4 years. Use the modified duration to estimate the new price P if the yield rises by 100 basis points.

P0 = €940y = 3%D = 6.4Δy = +100 bp
P = €
7.CAPM & WACCMedium
WACC = 11.03%equity€5 000 000re​ = ?debt€2 000 000rd​ = 4.5%T = 20%

A company has equity worth €5 000 000 and debt worth €2 000 000. Its WACC is 11.03%, its pre-tax cost of debt is 4.5% and the tax rate is 20%. Find the cost of equity re.

E = €5 000 000D = €2 000 000WACC = 11.03%rd = 4.5%T = 20%
re = %
8.CAPM & WACCHard
rf​ = 1.5%, rm​ − rf​ = 4%D/E = 0.25equityβL​ = 1.5debtD/E = 1.25equityre​ = ?debtT = 28%

A company's shares have a beta of 1.5 at its current debt-to-equity ratio of 0.25. It plans to raise its debt-to-equity ratio to 1.25. The tax rate is 28%, the risk-free rate 1.5% and the market risk premium 4%. Find the cost of equity re after the change.

βL = 1.5D/E1 = 0.25D/E2 = 1.25T = 28%rf = 1.5%rm − rf = 4%
re = %
9.Descriptive statisticsMedium
2025303540455055

Find the sample standard deviation s of the data: 38, 16, 55, 45, 22, 47, 37.

n = 7
s =
10.Descriptive statisticsHard
z −2−1012

A quantity is normally distributed with mean 500 and standard deviation 50. What proportion P of values is below 400?

μ = 500σ = 50x = 400
P =
11.ProbabilityMedium
red: 3blue: 6

A bag holds 3 red and 6 blue balls. You draw two balls without putting the first one back. What is the probability P that both are red?

3 / 6
P =
12.ProbabilityHard
n = 12, p = 0.7: P(X = 2) = ?k0123456789101112

A test has 12 multiple-choice questions. A student who guesses gets each one right with probability 0.7, independently. What is the probability P of exactly 2 correct answers?

n = 12p = 0.7k = 2
P =
13.Normal distributionMedium
−3−2−10123zshaded area between −z and z = 0.2586

Drag z so that the shaded area between −z and z under the standard normal curve is 0.2586. Find z to two decimals.

A = 0.2586
z =
14.Normal distributionHard
4 s0X − Y?

Runner A's lap time X and runner B's lap time Y are independent and normal: X has mean 52 s and standard deviation 4 s, Y has mean 48 s and standard deviation 3 s. Find the probability P that X is greater than Y. Round z to two decimals.

μX = 52 s, σX = 4 sμY = 48 s, σY = 3 s
P =
15.Confidence intervalsMedium
μ₁ − μ₂0LUx̄₁ − x̄₂E = ?95%

The battery life of two phone models is compared. Model 1: 80 phones, mean 129 h, known standard deviation 20 h. Model 2: 80 phones, mean 135.5 h, known standard deviation 20 h. Find the margin of error E of the 95% confidence interval for μ₁ − μ₂.

n₁ = 80x̄₁ = 129 hσ₁ = 20 hn₂ = 80x̄₂ = 135.5 hσ₂ = 20 h95%
E = h
16.Confidence intervalsHard
σ = 33, n = ?x̄ − Ex̄ + Ex̄E = 199%

The population standard deviation is 33. How large a sample n do you need so that a 99% confidence interval for the mean has a margin of error of at most 1?

σ = 33E = 199%
n =
17.Hypothesis tests & confidence intervalsMedium
−2.382.38p = ?

The mean of a population is claimed to be 120; the population standard deviation is known to be 18. A random sample of 36 observations has a mean of 112.86. Test H₀: μ = 120 against H₁: μ ≠ 120. Find the p-value p.

μ₀ = 120σ = 18n = 36x̄ = 112.86H₁: μ ≠ μ₀
p =
18.Hypothesis tests & confidence intervalsHard
H₀H₁μ₀x̄cμ₀ + 3α = 0.05βσ = 7, power 95%, n = ?

A one-sided z test at α = 0.05 must detect a shift of the mean of 3 units with a power of 95%. The standard deviation is 7. Find the minimum sample size n.

α = 0.05power = 95%δ = 3σ = 7zα = 1.645zβ = 1.645
n =
19.Linear regression & correlationMedium
xy129236339447546651xy246304050

The table gives 6 paired observations of x = advertising spend in k€ and y = sales in k€. Find the coefficient of determination r² of the least-squares line.

n = 6
r² =
20.Linear regression & correlationHard
xy129226322423519617xy246202530x = 3.5

The table gives 6 paired observations of x = car age in years and y = price in k€. Use the least-squares line ŷ = a + b·x. A new observation (3.5, 18) is made. Find its residual e = y − ŷ.

n = 6(3.5, 18)
e =

3Solutions

1.Time value of money

Answer: EAR = 20.97 %

Time value of money: money today is worth more than the same amount later, because it can earn interest. With interest rate i per period, an amount grows as FV = PV·(1 + i)n. A series of equal payments (an annuity) is valued by adding up each payment, which gives the annuity formulas.

Rate per period

r/m = 0.195/4 = 0.04875

Compound over one year

EAR = (1 + 0.04875)4 − 1 = 1.21 − 1 = 20.97%

Answer

EAR = 20.97%

The EAR is always above the nominal rate when interest compounds more than once a year.

2.Time value of money

Answer: FV = 97086 €

Time value of money: money today is worth more than the same amount later, because it can earn interest. With interest rate i per period, an amount grows as FV = PV·(1 + i)n. A series of equal payments (an annuity) is valued by adding up each payment, which gives the annuity formulas.

Monthly rate and number of deposits

i = 0.036000000000000004/12 = 0.003
N = 12·25 = 300

Future value of the deposits

FV = A·((1 + i)N − 1)/i = 200·(2.456 − 1)/0.003 = €97 086.10

Answer

FV = €97 086.10

You paid in €60 000 yourself; the rest is interest.

3.NPV & IRR

Answer: DPB = 4.215 years

Payback period: the time until the cumulative cash flows repay the initial investment. Cash is assumed to come in evenly during each year, so the last part is a fraction of a year. The simple payback ignores the time value of money; the discounted payback period uses the discounted cash flows instead.

Discounted and cumulative cash flows

year 1: 18 000/1.12 = 16 071.43 → Σ = 16 071.43
year 2: 14 500/1.254 = 11 559.31 → Σ = 27 630.74
year 3: 26 000/1.405 = 18 506.29 → Σ = 46 137.03
year 4: 17 500/1.574 = 11 121.57 → Σ = 57 258.59
year 5: 22 500/1.762 = 12 767.10 → Σ = 70 025.70

Fraction of the last year

DPB = 4 + 2 741.41/12 767.10 = 4.215

Answer

DPB = 4.215 years

The discounted payback is always longer than the simple payback (3.086 years).

4.NPV & IRR

Answer: IRR = 25.02 %

Net present value: discount every cash flow back to today with the required rate of return r, then add them up: NPV = Σ CFₜ/(1 + r)ᵗ. A project with NPV > 0 earns more than r and adds value. The internal rate of return (IRR) is the rate at which NPV = 0.

Bracket the IRR

NPV falls as the rate rises, so the IRR lies between a rate with positive NPV and one with negative NPV.

NPV(25%) = 16.00
NPV(30%) = −3 199.82

Narrow down

Linear interpolation gives a first estimate; repeating it (or a calculator's IRR function) gives the exact rate.

IRR ≈ 25 + 5·16.00/(16.00 − (−3 199.82)) = 25.02%
exact: NPV(25.02%) = 0 → IRR = 25.02%

Answer

IRR = 25.02%
5.Bond pricing & yield

Answer: P = 917.4 €

Bond pricing: a bond’s price is the present value of its cash flows, discounted at the yield to maturity (YTM): the coupons form an annuity and the face value is paid back at maturity. P = C·(1 − (1 + y)⁻ⁿ)/y + F/(1 + y)ⁿ. When the yield is above the coupon rate the bond trades below face value, and the other way round.

Per period

C = €10.00, i = 0.025, N = 6

Present value of the coupons

€10.00·(1 − 0.8623)/0.025 = €55.08

Present value of the face value

€1 000·0.8623 = €862.30

Price

P = €917.38

Answer

P = €917.38

The yield is above the coupon rate, so the bond sells at a discount.

6.Bond pricing & yield

Answer: P = 881.6 €

Duration: the Macaulay duration is the weighted average time at which a bond pays its cash flows, with the present values of the cash flows as weights: D = Σ t·PVₜ/P. The modified duration D/(1 + y) estimates the percentage price change for a small change in yield: %ΔP ≈ −Dmod·Δy.

Modified duration

Dmod = 6.4/1.03 = 6.214

Estimated price change

%ΔP ≈ −6.214·(0.01) = −6.214%
P ≈ 940·(1 − 0.06214) = €881.59

Answer

P = €881.59

Duration is a linear estimate; for large yield changes convexity makes the true price a little higher.

7.CAPM & WACC

Answer: re = 14 %

Cost of capital: CAPM gives the return shareholders require: re = rf + β·(rm − rf). The weighted average cost of capital mixes equity and debt by their market values: WACC = E/V·re + D/V·rd·(1 − T), with V = E + D. Interest is tax-deductible, hence the (1 − T).

Weights

V = €7 000 000, E/V = 0.7143, D/V = 0.2857

Debt part of the WACC

0.2857·4.5%·(1 − 0.2) = 1.029%

Cost of equity

re = (11.03% − 1.029%)/0.7143 = 14%

Answer

re = 14%
8.CAPM & WACC

Answer: re = 11.16 %

Levered beta (Hamada): debt makes equity riskier. βL = βU·(1 + (1 − T)·D/E), where βU is the beta of the business without debt. To move a beta to another capital structure, unlever it first and then relever it at the new D/E.

Unlever the beta

βU = 1.5/(1 + 0.72·0.25) = 1.271

Relever at the new D/E

βL = 1.271·(1 + 0.72·1.25) = 2.415

Cost of equity (CAPM)

re = 1.5% + 2.415·4% = 11.16%

Answer

re = 11.16%
9.Descriptive statistics

Answer: s = 13.87

Descriptive statistics: the mean is the sum divided by n; the median is the middle value of the sorted data (the average of the two middle values when n is even). The sample standard deviation is s = √(Σ(x − x̄)²/(n − 1)). A z-score z = (x − μ)/σ says how many standard deviations a value lies from the mean.

Mean

x̄ = 260/7 = 37.14

Squared deviations

Σ(x − x̄)² = 0.8571² + (−21.14)² + 17.86² + 7.857² + (−15.14)² + 9.857² + (−0.1429)² = 1155

Standard deviation

s = √(1155/6) = 13.87

Answer

s = 13.87
10.Descriptive statistics

Answer: P = 0.02275

Descriptive statistics: the mean is the sum divided by n; the median is the middle value of the sorted data (the average of the two middle values when n is even). The sample standard deviation is s = √(Σ(x − x̄)²/(n − 1)). A z-score z = (x − μ)/σ says how many standard deviations a value lies from the mean.

Standardise

z = −2

Standard normal table

Φ(−2) = 0.02275
P = 0.02275

Answer

P = 0.02275
11.Probability

Answer: P = 0.08333

Probability: with equally likely outcomes, P(A) = favourable/total. For independent events multiply: P(A and B) = P(A)·P(B). The complement often helps: P(at least one) = 1 − P(none). Binomial: in n independent trials with success probability p, P(X = k) = C(n, k)·pᵏ·(1 − p)ⁿ⁻ᵏ.

First and second draw

P = 3/9 · 2/8 = 6/72 = 0.08333

Answer

P = 0.08333
12.Probability

Answer: P = 0.000191

Probability: with equally likely outcomes, P(A) = favourable/total. For independent events multiply: P(A and B) = P(A)·P(B). The complement often helps: P(at least one) = 1 − P(none). Binomial: in n independent trials with success probability p, P(X = k) = C(n, k)·pᵏ·(1 − p)ⁿ⁻ᵏ.

Binomial formula

P(X = 2) = 66·0.72·0.310 = 66·0.49·5.905 × 10⁻⁶ = 0.000191

Answer

P = 0.000191
13.Normal distribution

Answer: z = 0.33

From an area back to z: Φ(z) is the area to the left of z. For a left-tail area A, find z with Φ(z) = A in the table. A right-tail area A means Φ(z) = 1 − A. A central area A between −z and z leaves (1 − A)/2 in each tail, so Φ(z) = (1 + A)/2. For a value x, use x = μ + zσ.

Area to the left of z

Φ(z) = (1 + 0.2586)/2 = 0.6293

Read the z-table backwards

Find 0.6293 inside the table and read off z.

z = 0.33

Answer

z = 0.33
14.Normal distribution

Answer: P = 0.7881

Sums and differences of normal variables: if X and Y are independent and normal, X + Y and X − Y are normal too. Means add or subtract: E(X ± Y) = μX ± μY. Variances always add, also for a difference: Var(X ± Y) = σX² + σY², so σ = √(σX² + σY²). Standard deviations never add directly. The total of n independent items with the same distribution has mean n·μ and standard deviation σ·√n. Then standardise as usual: z = (x − mean)/σ and read Φ(z).

Distribution of the difference

μ = 52 − 48 = 4 s, σ = 5 s

Standardise

z = (0 − 4)/5 = −0.8

Probability

P = 1 − Φ(−0.8) = 0.7881

Answer

P = 0.7881
15.Confidence intervals

Answer: E = 6.198 h

Interval for a difference: estimate ± critical value × standard error. For two independent means with known σ: SE = √(σ₁²/n₁ + σ₂²/n₂) and z. With equal unknown variances: pooled s_p and t with n₁ + n₂ − 2 degrees of freedom. For paired data, work with the differences: d̄ ± t·s_d/√n.

Point estimate

x̄₁ − x̄₂ = 129 − 135.5 = −6.5

Standard error

SE = √(20²/80 + 20²/80) = 3.162

Margin of error

E = 1.96·3.162 = 6.198

Answer

E = 6.198 h

The interval does not contain 0, so the means differ significantly.

16.Confidence intervals

Answer: n = 7227

Confidence interval for a mean: x̄ ± margin of error. With a known population σ the margin is z·σ/√n; with only the sample standard deviation s, use t with n − 1 degrees of freedom: t·s/√n. Critical values: z = 1.645 (90%), 1.96 (95%), 2.576 (99%). To get a margin E or smaller, you need n ≥ (z·σ/E)², rounded up.

Solve for n

n = (2.576·33/1)² = 7226

Round up

A sample size is a whole number, and rounding down would make the margin too large.

n = 7227

Answer

n = 7227
17.Hypothesis tests & confidence intervals

Answer: p = 0.01731

Hypothesis test: the test statistic = (estimate − value under H₀)/(standard error under H₀). The p-value is the probability, assuming H₀ is true, of a statistic at least as extreme as the one observed: the area in one tail for a one-sided H₁, twice the tail area for a two-sided H₁. Reject H₀ when p ≤ α.

Test statistic

SE = σ/√n = 18/√36 = 3
z = (112.86 − 120)/3 = −2.38

Tail area

Φ(2.38) = 0.9913
1 − Φ(2.38) = 0.0087

p-value

p = 2·0.0087 = 0.01731

Answer

p = 0.01731

p ≤ 0.05, so H₀ is rejected at the 5% level.

18.Hypothesis tests & confidence intervals

Answer: n = 59

Sample size for a test: to detect a true shift δ with power 1 − β in a one-sided z test at level α, the standard error must satisfy δ = (z_α + z_β)·σ/√n, so n = ((z_α + z_β)·σ/δ)², rounded up.

Solve for n

n = ((1.645 + 1.645)·7/3)² = 58.93

Round up

n = 59

Answer

n = 59
19.Linear regression & correlation

Answer: r² = 0.9387

Least-squares regression: with x̄ and ȳ the means, Sxx = Σ(x − x̄)², Syy = Σ(y − ȳ)² and Sxy = Σ(x − x̄)(y − ȳ), the line ŷ = a + b·x has slope b = Sxy/Sxx and intercept a = ȳ − b·x̄, so it always passes through (x̄, ȳ). Pearson's correlation coefficient r = Sxy/√(Sxx·Syy) lies between −1 and 1; r² is the fraction of the variation in y explained by the line.

Means

x̄ = 21/6 = 3.5
ȳ = 248/6 = 41.33

Sums of squares and products

Sxx = Σ(x − x̄)² = 17.5
Sxy = Σ(x − x̄)(y − ȳ) = 74
Syy = Σ(y − ȳ)² = 333.3

Coefficient of determination

r² = 74²/(17.5·333.3) = 0.9387

Answer

r² = 0.9387

About 93.87% of the variation in y is explained by the line.

20.Linear regression & correlation

Answer: e = −4.667

Least-squares regression: with x̄ and ȳ the means, Sxx = Σ(x − x̄)², Syy = Σ(y − ȳ)² and Sxy = Σ(x − x̄)(y − ȳ), the line ŷ = a + b·x has slope b = Sxy/Sxx and intercept a = ȳ − b·x̄, so it always passes through (x̄, ȳ). Pearson's correlation coefficient r = Sxy/√(Sxx·Syy) lies between −1 and 1; r² is the fraction of the variation in y explained by the line.

Means

x̄ = 21/6 = 3.5
ȳ = 136/6 = 22.67

Sums of squares and products

Sxx = Σ(x − x̄)² = 17.5
Sxy = Σ(x − x̄)(y − ȳ) = −40

Regression line

b = −40/17.5 = −2.286
a = 22.67 − (−2.286)·3.5 = 30.67
ŷ = 30.67 − 2.286·x

Predicted value

ŷ = 30.67 + (−2.286)·3.5 = 22.67

Residual

e = 18 − 22.67 = −4.667

Answer

e = −4.667

The point lies below the line.

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