# Shared Flashcard Set

## Details

Biometry Exam 1
barf
52
Mathematics
09/18/2013

Term
 What are data?
Definition
 Observations we objectively make of our environment
Term
 Why do we use statistical analysis?
Definition
 Dram conclusions, better understand the source of the data, data reduction, inference, ID relationships and associations,
Term
 What is a discrete random variable?
Definition
 Has non-measurable gaps between values (ex: cow shit scores)
Term
 What is a continuous random variable?
Definition
 any value number is possible
Term
 What is a nominal scale?
Definition
 Pregnant or not, live or dead, etc (mutually exclusive categories)
Term
 What is an ordinal scale?
Definition
 Ranked categories (cow shit, beef quality grades, etc.)
Term
 What is an interval scale?
Definition
 Quantitative, but no true zero exists (his example was temp)
Term
 What is a ratio scale?
Definition
 "Highest level of measurement" - has a true zero
Term
 What is a population?
Definition
 A well-defined collection of entities - may be finite or infinite
Term
 What is the sample population?
Definition
 A representative sample of the entire population
Term
 What is a descriptive statistic?
Definition
 A single calculated number that conveys important info about the data from which is was calculated
Term
 The average human being has one breast and one testicle
Definition
 That is all.
Term
 What is an ordered array?
Definition
 The simplest form of data organization used to calc min, max, and range
Term
 What is an advantage of a stem and leaf plot?
Definition
 It conserves information about individual measurements
Term
 What are 3 measures of central tendency?
Definition
 Mean, median and mode
Term
 Why does snoop dog carry an umbrella?
Definition
 FO DRIZZLE!
Term
 What's the difference between mew and bar x?
Definition
 mew = pop mean, bar x = sample mean
Term
 What's dispersion?
Definition
 The variation in a data set
Term
 What is sample variance?
Definition
 Subtract the mean from every value (residual), square the results, sum them, and divide by n-1 (degrees of freedom)
Term
 What is pop variance?
Definition
 Subtract the mean from every value (residual), square the results, sum them, and divide by N (degrees of freedom)
Term
 Explain degrees of freedom
Definition
 The deviations from the mean will always sum to zero. If we know the values of (n-1) of the observations and the value of the mean, we can, using simple algebra, determine the value of the unknown observation. Therefore, all of the observations except for 1 (n-1) are ‘free to vary.’
Term
 Within how many St dev do most of your data lie?
Definition
 Almost all data of any data set will lie with 3 STD of either side of the mean
Term
 How do you calculate sample variance? Pop variance?
Definition
 square root of s^2, square root of that funny looking o
Term
 What is the interquartile range?
Definition
 Q3-Q1 - the difference between the 3rd and 1st quartiles
Term
 What 2 things do descriptive stats tell you?
Definition
 Central tendency and dispersion
Term
 What's the eqn for probability?
Definition
 P(E)=m/N
Term
 What's the eqn for relative frequency probability?
Definition
 P(E)=m/n - this works if there is a large sample
Term
 What are 3 properties of the Probability Theory as stated by Kolmogorov?
Definition
 1.P(any event) must be a non-negative number2.Sum of mut excl events all add to 13.Prob of any 2 mut excl events is equal to the sum of their probabilities
Term
 What is conditional probability?
Definition
 The probability of an event, given certain circumstances (what is the prob a cow has had bloat 5 times, given that animal is male?) P(C | M)?
Term
 What is joint prob?
Definition
 Probability of an event given 2 or more characteristics (what is the prob a cow has had bloat 5 times and that animal is male?)
Term
 What is the multiplication rule?
Definition
 We can compute a joint probability as the product of an appropriate unconditional probability and an appropriate conditional probability, which is called the Multiplication RuleP(M ∩ C) = P(M)*P(C | M)
Term
Definition
 Given two events A and B, the probability that event A, or event B, or both occur is equal to the probability that event A occurs, plus the probability that event B occurs, minus the probability that the events occur simultaneously P(M∪ C) = P(M) + P(C) – P(M ∩ C)P(A or B) = P(A) + P(B) when A and B are mutually exclusive events
Term
 How do you calculate prob of independent events?
Definition
 Events are considered independent if Event B occurring has no effect on the probability of Event A occurring. This is not the same concept as mutually exclusive.P(A|B)=P(A)
Term
 What is the multiplication rule or independent events?
Definition
 If two events are independent, the probability of their joint occurrence is equal to the product of the probabilities of the individual occurrencesP(A∪B) = P(B)*P(A); P(A) ≠ 0 and P(B) ≠ 0
Term
 P(A|B) = P(A)P(B|A) = P(B)P(A∩B) = P(A)*P(B)These statements are true for what type of events?
Definition
 Independent
Term
 What is a false positive?
Definition
 a test indicates a positive result when the true result is negative
Term
 What is a false negative?
Definition
 a test indicates a negative result when the true result is positive
Term
 What is Baye's Theorem?
Definition
 I skipped it because he skipped it. I think. It's really long and stupid.
Term
 What does a nosy jalapeno do?
Definition
 Gets jalapeno buisnazzz
Term
 Name 3 qualities of probabilities of discrete, random variables
Definition
 All probabilities are positiveAll probabilities are less than 10 ≤ P(X = x) ≤ 1All exhaustive probabilities sum to 1∑ P(X = x) = 1
Term
 How do you calculate cumulative probability?
Definition
 Cumulative Probability is obtained by successively adding the probabilities, P(X = x), given in the last column of the probability distributionWritten as P(X ≤ xi), gives probability that X is less than or equal to a specified value, xi
Term
Definition
 A Bernoulli Trial is any process or event that:Results in one of two possible, mutually exclusive, outcomes. The probability of a success, p, remains constant from trial to trial. The probability of a failure, q, is 1 – p.The trials are independent; the outcome of any particular trial is not affected by the outcome of any other trial.
Term
 What is the multiplication rule?
Definition
 pqppq = p3q2 via multiplication rule
Term
 What is the equation for factorial?
Definition
 nCx = n!/x!(n-x)!
Term
 What are the parameters of binomial distributions?
Definition
 n and p are the only 2 parameters of binomial distributions
Term
 What is a continuous random variable?
Definition
 A Continuous Random Variable is one that can assume any value within a specific interval of values assumed by the variable. eg: there are an infinite number of values of the variable.
Term
 What is the most important distribution in stats?
Definition
 The normal one! AKA Gaussian dist
Term
 Mean and standard deviation measure what?
Definition
 The parameters mean and standard deviation can be thought of as measures of central tendency and dispersion
Term
 What are characteristics of the normal distribution?
Definition
 Symmetrical about the meanMean = median = modeTotal AUC about the x-axis is one square unit. – 50% of the area is to the left of the mean and 50% is to the right of the meanIf we erect perpendiculars a distance of 1 SD from the mean in both directions, the area ~ 68% of the total area (see figure previous page)Distribution determined by the parameters mew and funny o
Term
 How do you calculate z score?
Definition
 z=(x-mew)/funny o
Term
 21.What’s brown and sticky?
Definition
 A stick!
Term
 What is the difference between joint and conditional probabilities?
Definition
 joint - the events are independentP(A and B)=P(A)*P(B)conditional - the events are dependentP(A and B)=P(A)*P(B|A)
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