Term

Definition
the science of collecting, classifying, summarizing, organizing and interpreting data 


Term

Definition
the object upon which we
collect data. It is the source of
each “observation”.
In our water research, it is a
bit of water taken from a
segment of the brook at a
particular time. 


Term

Definition
a characteristic of the
experimental unit that is
measured from one
observation to the next.
In our water research, it could be concentration of nitrate 


Term

Definition
a collection of data on all experimental units. The population is all possible observations. 


Term

Definition
a subset of the population 


Term

Definition
summarize the sample data 


Term

Definition
use the sample data to say something about the population
give a measure of reliability (i.e. precision, confidence) about the population parameters 


Term

Definition
a list of all units in the population. 


Term

Definition
every unit in the population has the same probability of being selected for the sample and the probabilities are independent 


Term
Stratified Random Sampling 

Definition
the population units are partitioned into strata, then simple random sampling is carried out in each stratum 


Term

Definition
units are selected according to clusters 


Term

Definition
every Kth element is selected 


Term

Definition
exists when some subset of the population has uneven and unaccounted for probability of selection
Nonresponse in surveys can be a type of bias 


Term

Definition
is the difference between the actual value of the variable and the recorded value of the variable. Measurement error can be a type of bias.
A faulty thermometer can produce measurement error 


Term

Definition
refers to the natural variation in any simple random sample.
Not mistake.
1.Bias + Sampling Error = the difference between reality and your observations = TOTAL ERROR



Term

Definition
–Mean is the average
–Median is the middle
observation of ordered data
•Definition is slightly different for
Odd n versus Even n
Mode is the value that occurs with the greatest frequency 


Term

Definition
–Range = Maximum minus
Minimum
–Variance
–Standard Deviation is square root of variance
•When the distribution is bell shaped:
–about 70% of observations are within one standard deviation of the mean
–about 95% of observations are within two standard deviations of the mean
–Interquartile range = 3rd Quartile minus 1st Quartile



Term

Definition
the value at which P% of the observations fall on or below and (100P)% of the observations fall above
•Max is 100th percentile
•Third quartile is 75th percentile
•midquartile is 50th percentile, which is the median
•First quartile is 25th percentile
•Min is 0th percentile



Term

Definition
Zscore = ( Xi – Xbar ) / s, where s is the standard deviation 


Term

Definition
•Candidates for outliers have zscores less than –3 or greater than +3 


Term

Definition
If the distribution is symmetric, then it is not skewed
If the tail of the distribution extends to the right, then the distribution is skewed right, i.e. skewed in the positive direction
If the tail of the distribution extends to the left, then the distribution is skewed left, i.e. skewed in the negative direction 


Term
•Notation for population parameters and sample statistics on page 179 

Definition
–Mean
•Mu is parameter, Xbar is statistic
–Variance
•sigma2 is parameter, s2 is statistic
–Standard Deviation
•sigma is parameter, s is statistic
–Zscore
•z is parameter, z is statistic
–Correlation coefficient
•rho is parameter, r is statistic 


Term

Definition


Term
Frequentist view of probability 

Definition
–Probability is the number of times that an event happens divided by the number of trials 


Term
Bayesian view of probability 

Definition
Probability is a person’s subjective judgment concerning the likelihood of an event, based on the information that the person has 


Term

Definition
is the process of making
observation(s) on unit(s)
–Selecting a card from a deck
–Flipping a thumbtack
–Observing the cloudiness of the sky



Term

Definition
the outcome of an experiment
–The card is red
–The thumbtack lands point up
–Sky is Clear



Term

Definition
the collection of all possible events
–Red Card or Black Card
–The thumbtack lands in the point up or point down position
–Sky can be: Clear, Few Clouds, Many Clouds, Other



Term
Definitions illustrated by Venn diagrams 

Definition
–Experiment, Event, Sample Space, Probability, Mutually exclusive events, Complement of an event, Conditional probability of A given B, Independent, Intersection, Union 


Term
The Probability of an event A 

Definition
denoted P(A) is a real number between 0 and 1 that indicates the likelihood that event A will occur when the experiment is performed. 


Term
The Complement of an event A 

Definition
denoted A´, is the event that A does not occur. 


Term
The Intersection of A and B 

Definition
the event that both A and B occur. 


Term

Definition
the event that A or B occur
1.P(A or B) = P(A) + P(B) – P(A and B)



Term
A and B are mutually exclusive events 

Definition


Term
The probability of A given B 

Definition
denoted P(AB), is P(A ∩ B)/P(B) 


Term

Definition
means P(A) = P(AB) = P(A ∩ B)/P(B)
–Which implies that A and B are independent if and only if P(A ∩ B) = P(A) * P(B)


