1 Flashcards
Continuous normal distribution
is described by a lower limit, a, and an upper limit, b. These limits serve as the parameters of the distribution.
in Continuous normal distribution, the probability of any outcome or range of outcomes outside the limits a, and b is ____
0
give the probability of random variables being outside the parameters of a continuous distribution
P(Xb) = 0
P(X ≥ x) is the same as P(X ﹥ x) for a continuous distribution because P(X = x) equals ____.
- zero
in a continuous distribution, the probability that a random variable, X will take a value that falls between x_1 and x_2 within the range a to b is…
the proportion of the area from x_1 to x_2 divided by the area from a to b –>
P(x1≤X≤x2) = (x_2 - x_1) / b-a
normal distribution shape is..
- ## bell shaped
Normal distribution is completely described by its mean (μ) and variance (σ2). The distribution is stated as X ∼ N (μ,σ2), which is read as ….
- the random variable X follows the normal distribution with mean, μ and variance, σ2.
The normal distribution has a skewness of 0, which means that it is ______ about its mean. P(X≤mean)=P(X≥mean)=.5
- symmetric
normal distribution mean, median, modes, are…
all the same, betch
whats the kurtosis of standard normal distribution? whats the excess kurtosis?
3 and excess = 0
if the returns on each stock in a portfolio is a linear distribution, the portfolio has a ________
linear dist as well
describe probability of a random variable lying in ranges further away from the mean in a normal distribution..
probability gets lower and lower the further away from the mean, but never reaches zero
univariate distribution..
describe the distribution of a single random variable – up to this point, we have only dealt with this shit
multivariate distribution
specify probabilities associated with a group of random variables taking into account the interrelationships that may exist between them.
multivariate example?
a linear combination of normally distributed variables al put together in a portfolio would still have a normal distribution – this is said to have a multivariate normal distribution
the need to know _____ is what differentiates multivariate normal distributions from univariate normal distributions.
- correlations
A multivariate normal distribution for the return on a portfolio with n stocks is completely defined by the following three parameters:
- The mean returns on all the n individual stocks (μ_1,μ_2,…..,μ_n)
- The variances of returns of all n individual stocks (σ_1^2,σ_2^2,…..,σ_n^2)
- The return correlations between each possible pair of stocks. There will be n(n-1)/2 pairwise correlations in total. (Correlation is a measure of the strength of the linear relationship between 2 variables).3
If we are studying returns on a portfolio consisting of 4 assets, we will use __ means, __ variances, and the ___ correlations to describe the multivariate distribution.
- 4
- 4
- 6
A confidence interval represents …
the range of values within which a certain population parameter is expected to lie in a specified percentage of the time.
in practice we do not know the population parameters, so we…
estimate them
the three confidence intervals that we encounter most frequently are
90%
95%
99%
for: 90%
95%
99%, what are their respective standard deviations from the mean?
90% = +or - 1.65s
95% = + or - 1.96s
99% = + or - 2.58s