Quant First Half

Question 1

What does µ represent?

Answer 1

population mean

Question 2

If a distribution is symmetrical, what does it mean for mean and median?

Answer 2

Mean = Median

Question 3

Formula to calculate median

Answer 3

Position = (N+1)/2

Question 4

How to calculate deviation?

Answer 4

(𝑋𝑖 − x̄)

Question 5

How to calculate variance?

Answer 5

(Xi-x̄)^2/n

Question 6

Symbol for standard deviation

Answer 6

σ

Question 7

How to calculate σ

Answer 7

1. find the mean of samples
2. Find square differences (The data value - mean)^2
3. Find averages of square differences
4. Find square root

Question 8

Standard display of distribution

Answer 8

N(μ,σ)
N(mean, standard deviation)

Question 9

% of values within 1 SD/σ

Answer 9

68.3%

Question 10

% of values within 2 SD/σ

Answer 10

95.4%

Question 11

% of values within 3 SD/σ

Answer 11

99.7%

Question 12

Observations more than 3 SD/σ away from the mean are:

Answer 12

outliers

Question 13

Formula for Z Score

Answer 13

Z = (x-μ)/σ

Z = (sample - mean) / Standard deviation

Question 14

Sample space for tossing coin 3 times

Answer 14

S = {HTH, HHT, HHH, THT, THH, TTT, TTH, HTT}

Question 15

Notation for Union Probability

Answer 15

P (A or B), or P(AUB)

Question 16

Notation for Joint/Intersection Probability

Answer 16

P (A and B), or P(A ∩ B)

Question 17

Notation for Conditional Probability (Chance of A given B)

Answer 17

P (A|B)

Question 18

How to calculate probability of one of two events (union probability)

Answer 18

P (A or B) = P(A) + (B) - P(A and B)

Question 19

How to calculate probability of two events both happening

Answer 19

P(A and B) = P(A)P(B|A) (NB: this is for if probability is related. If they are independent events, it’s just P(A)P(B)