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Biometry Exam 1
barf
52
Mathematics
Graduate
09/18/2013

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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 number
2.Sum of mut excl events all add to 1
3.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 Rule

P(M ∩ C) = P(M)*P(C | M)
Term
What is the addition rule?
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 occurrences

P(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 positive
All probabilities are less than 1
0 ≤ P(X = x) ≤ 1
All 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 distribution
Written as P(X ≤ xi), gives probability that X is less than or equal to a specified value, xi
Term
Tell me about Bernoulli trials
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 mean
Mean = median = mode
Total 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 mean
If 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 independent
P(A and B)=P(A)*P(B)

conditional - the events are dependent
P(A and B)=P(A)*P(B|A)
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