stats Flashcards
Quantitative data what ?
Numerical values :
what is continuous data?
Continuous data: It represents variables that cannot be counted but can be measured.
Discrete data: It can take up only integer values
The set of all possible outcomes is called
The sample space.
When we repeat a random experiment several times, we call each one of them a.
Trial
Any subset of the sample space is called an
Event
We can either get an even number, or an odd
number, but not both. Such events are called ?
Mutually exclusive
Bayesian statistics, a posterior probability
The posterior probability is calculated by updating the prior probability using Bayes’ theorem.
Example of mutually-exclusive event
Both football teams can’t win mutually-exclusive events
Probability density function : gives the probability that a discrete random variable X is equal to a certain value
Example of discrete variable.
Countable outcome, kids in a class
Continuous random variable
Continuous random variable can take an infinite number of outcomes, eg height
Area Under The Curve:
Which represents the total probability, in the case of
continuous variables
The y-axis in a probability density function represents
Is the probability.
What is Exponential distribution ?
A continuous distribution, that is often used to model the expected time one needs to wait
A left-skewed distribution or negatively skewed: has a long tail, in which direction ?
Left tail, the mean is less than the mode.
A right-skewed distribution or positively skewed distribution, has a long tail in
The right direction
Higher kurtosis implies ?
fatter tails, more probability for extreme values happening > 3 leptokurtic more risky.
Mesokurtic Distribution
Normal distribution
Leptokurtic Distribution
Thin & tall with fatter tails, higher to lep over, more risky
Platykurtic Distribution
Fat and wide shallow: like a plate
log-normal distribution
Income of people
T-distribution is measured in
Degrees of freedom
What is exponential distribution used to measure ?
Probability distribution, of time between events
Standard normal distribution is when ?
The mean is close to zero and standard deviation is 1.
Which distributions is often used to model the asset prices? As they are not negative
A lognormal distribution i
T -distribution has fat or thin tails ?
T has fatter tails then normal distribution
What is Inferential statistics
Extrapolating data to help predictions
CLT
Central limit theorem, helps us predict confidence intervals
The population
Is a superset of a sample and a representative sample of a larger group
The sample mean is a random variable as it varies from sample to sample.
Yes
Hypothesis is held true
Until we have evidence to reject
The p-value
The probability of observing a more extreme value than that of the test statistic, proves the null hypothesis is true
Type I error
Rejection of an actually true null hypothesis
Type II error
The failure to reject a null hypothesis that is actually false
A statistical hypothesis is a factual statement that
That is about a population parameter which may or may not be true.
The significance level or p-value is found first
Yes, setting significance value in advance, helps us to avoid bias
If p-value is less than the chosen significance level then we ?
We reject the null hypothesis i.e. The sample gives reasonable evidence, to support the alternative hypothesis.