Estadística Apuntes

Chapter1 – Numerical Representation of Data

Sample mean = [pic][pic]= [pic] or by calculator


Unbiased estimate of variance = [pic]= [pic]= [pic]


Standard deviation = [pic]

If x ischanged to y using y = ax + b then
New mean [pic] new sd [pic]

Question
[pic]

ANSWER
[pic]
Chapter2 – Correlation and Regression

• Least squares regression line y = a + bx, where yis the dependent variable
• Product Moment Correlation Coefficient = r
Measures strength of linear relationship between variables
• Residual = table – line prediction
•Linear scaling has no effect on r but the regression line will change

Question
[pic]
ANSWERS
[pic] [pic] [pic]
Chapter 3 – Probability

‘NOT’ events: [pic] means “not A”. It is the event thatA does not happen.

‘AND’ events: [pic] means “A and B”. It is the event that A and B both happen.

‘OR’ events: [pic] means “A or B”. It the event that A happens or B happens or both.Conditional events: [pic] is read “A given B”. This is the event that A happens in a situation where we happen already to know that B has happened.

Probabilities of events: A capital P() is used to mean“the probability of”, so that P([pic]) means “the probability that A and B both happen", and so on.

• For any two events A and B, [pic]
• If two events A and B are mutually exclusive(which means that they can't both happen), then [pic] and the above formula becomes
[pic]
• [pic]
• For independent events, [pic]
• For probability questions that do not have a table ,use a probability TREE

Question
[pic]
ANSWERS
[pic]
Chapter 4 – Binomial

A Binomial distribution, which is used in situations when:

(a) an experiment is repeated a fixed number of times,denoted by n;
(b) at each individual repetition, there are only two possible outcomes, usually called "success" and "failure", and P(success) is denoted by p, so that P(failure) = 1 - p;
(c)...