Assignment 3

Question 1

Z-score

Answer 1

A standardized score in which the mean of a data set is subtracted from a number and the difference is then divided by the standard deviation. The calculation tells one how far a number is above or below the mean in terms of standard deviations.

Question 2

Sample space

Answer 2

The total possible outcomes in calculating a probability.

Question 3

Event

Answer 3

Some specified occurrence for calculating a probability.

Question 4

Normal distribution

Answer 4

In probability theory, the normal (or Gaussian) distribution is a continuous probability distribution, defined on the entire real line. It has a bell-shaped probability density function.

Question 5

Poisson distribution

Answer 5

A discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time, space, distance, area or volume if these events occur independently with a known average rate.

Question 6

Standard normal deviate

Answer 6

A z score of a normally distributed variable in a population.

Question 7

Addition rule

Answer 7

When two events, A and B, are mutually exclusive, the probability that A or B will occur is the sum of the probability of each event such that P(A or B) = P(A) + P(B).

Question 8

Multiplication rule

Answer 8

When two events, A and B, are mutually exclusive, the probability that A AND B will occur is the product of the probability of each event such that P(A and B) = P(A) x P(B).

Question 9

Sensitivity

Answer 9

The probability of testing positive given that a subject has some condition.

Question 10

Specificity

Answer 10

The probability of testing negative given that a subject does not have some condition.

Question 11

Law of large numbers

Answer 11

In probability theory, the average of the results obtained from a large number of trials will converge on the expected value, and will tend to become closer as more trials are performed.

Question 12

Prior probability

Answer 12

A probability as assessed before making reference to certain relevant observations, especially subjectively or on the assumption that all possible outcomes be given the same probability.

Question 13

Posterior probability

Answer 13

The statistical probability that a hypothesis is true calculated in the light of relevant observations.

Question 14

Standard normal curve

Answer 14

A normal distribution with a mean of 0 and a standard deviation of 1.

Question 15

Bayes Theorem/Rule

Answer 15

p(A|B) = p(B|A) x p(A) / p(B)

Question 16

Parameters

Answer 16

A characteristic of a distribution (such as the mean) in a population.

Question 17

Statistic

Answer 17

A characteristic of a distribution (such as the mean) in a sample.

Question 18

T-score

Answer 18

Used in testing, a score that reflects one’s relative standing in a reference group with a particular mean and standard deviation.

Question 19

Conditional probability

Answer 19

The probability of an event given that some condition has been met.

Question 20

Positive predictive value

Answer 20

The probability of having a condition given that a subject tests positive. (The flip side of sensitivity)

Question 21

Negative predictive value

Answer 21

The probability of not having a condition given that a subject tests negative. (The flip side of specificity).

Question 22

Contingency table

Answer 22

A table constructed with at least two factors that reveal the intersection of all levels. A contingency table is used in factorial ANOVA and with the chi-square test for association.