# Shared Flashcard Set

## Details

Biometrics Midterm 1
concepts
62
Biology
02/08/2015

Term
 biometrics
Definition
 to measure life using statistics appied to life
Term
 population
Definition
 entire collection of measurements from all the organisms the reasearcher's interested in (total)
Term
 parameter
Definition
 numerical feature of the population (mean)
Term
 sample
Definition
 subset of population
Term
 random samples
Definition
 every single individual in population has a chance
Term
 interspersed samples
Definition
 representative of population
Term
 biased
Definition
 does not accurately reflect the population of interest
Term
 statistic
Definition
 numerical feature of the sample
Term
 sampling error
Definition
 difference between sample statistic and the population parameter
Term
 scientific method
Definition
 1) observations/questions 2) hypothesis 3) experiment 4) results 5) analyze results with statistics 6) conclusion
Term
 individual
Definition
 - objects described by a set of data
Term
 variables
Definition
 characteristics of individuals
Term
 nominal-scale data
Definition
 qualitative (descriptive) data ex. gender, eye color
Term
 ordinal-scale data
Definition
 quantitative, unequal intervals, ranked values
Term
 interval-scale data
Definition
 quantitative, equal increments, no meaningful zero value
Term
 ratio-scale data
Definition
 quantitative, equal intervals, meaningful zero value
Term
 inferential statistics
Definition
 estimates of population parameters
Term
 numerical statistics
Definition
 numerical feature of a sample
Term
 mean
Definition
 central tendency fo ratio-interval scale data
Term
 grand (weighted) mean
Definition
 mean of means
Term
 median
Definition
 measure of central tendency used for ordinal-scale data (ranked) data
Term
 mode
Definition
 measure of central tendency used for nominal-scale data
Term
 dispersion
Definition
 (variability) sum of squares, variance, standard deviation, coefficient of variation (ratio-interval scale)
Term
 range
Definition
 measure of dispersion for ordinal-scale (difference between highest and lowest value)
Term
 diversity indices
Definition
 measures of dispersion for nominal-scale data (qualitative)
Term
 frequency distributions
Definition
 determines the probability of obtaining certain values  (histogram, probability density curve)
Term
 normal distributions
Definition
 greatest frequency of occurrence is at mean lowest frequency of occurence is at extremes distribution is symmetrical about the mean
Term
 right skewness
Definition
 asymmetrical, greater frquency of large values
Term
 left skewness
Definition
 asymmetrical, greater frequency of extreme small values
Term
 kurtosis
Definition
 peakedness, symmetrical
Term
 leptokurtosis
Definition
 all values are around mean
Term
 platykurtosis
Definition
 plateau, not peaked, greatest frequency are all values
Term
 standardized normal distribution
Definition
 mean - 0 standard deviation - 1 values converted to Z-scores
Term
 data distributions
Definition
 frequency distribution of raw data
Term
 sampling distributions
Definition
 frequency distribution of statistics (not raw data)
Term
 standard error
Definition
 - standard deviation of many means - single sample  - estimate of sampling distribution if multiple samples taken
Term
 central limit theorem
Definition
 - means of samples normally distributed as sample size increases - standard deviation will decrease as sample size increases
Term
 null hypotheses
Definition
 no difference or no relationship
Term
 alternative hypotheses
Definition
 there is a difference or relationship
Term
 there is a difference because
Definition
 1) populations are different 2) sampling error
Term
 objectivity
Definition
 achieved by using probabilities
Term
 P-value
Definition
 probability of obtaining your sample data and statistics from a population in which null hypothesis is true
Term
 type I error
Definition
 rejecting null hypothesis when it is true
Term
 type II error
Definition
 accepting null hypothesis when it is false
Term
 goodness-of-fit test
Definition
 - one nominal-scale variable, compare frequency distribution to a priori ratio-  DF = k -1 - R&B = n/k > 2
Term
 purpose of continuity correction
Definition
 reduce risk of getting large critical value and reduce risk of type I error
Term
 contingency table
Definition
 - two nominal-scale variables - frequency of occurrence of categories is independent of frequency of occurence of other variable - DF = (r-1)(c-1) - R&B = n/(r x c) > 6 - continuity correction (2x2)
Term
 one sample t-test
Definition
 - probability that sample of ratio-interval scale taken from a population with pre-determined mean  - mean = c (a priori constant)- DF = n-1two tailed: no difference one tailed: direction of difference
Term
 confidence intervals
Definition
 mean of population lies between two values
Term
 independent samples
Definition
 if values in one sample are not related in any particular way to values in other sample
Term
 paired samples
Definition
 if each value in one sample is associated with one particular value in the other sample
Term
 assumptions for two sample testing
Definition
 RSNDP (normal distribution) - D'Agostino Pearson K^2 test for normalityHomoscedastic (equal variances)
Term
 types of data transformation
Definition
 logarithmic transformation, square root transformation, arcsine square root transformation
Term
 nonparametric test
Definition
 assumptions are not met, ordinal-scale data. do not test for differences in the parameter (mean)
Term
 two sample t-test
Definition
 - tests for differences in the means of two independent samples of ratio-interval scale data- DF= (n1-1)(n2-1)- normal distributions, equal variances- nonparametric alternative: Mann-Whitney U test
Term
 Mann-Whitney U test
Definition
 tests for differences in the central tendency of two independent samples of ratio-interval scale data and ordinal-scale data (ranking) when assumptions of normality/homoscedasticity are not met- DF = n
Term
 outliers
Definition
 data points that are much more extreme than all of the other data in the sample
Term
 paired sample t-test
Definition
 - differences in the means of two paired samples of ratio-interval scale data, comparing difference between two means to zero- DF = n(d) - 1
Term
 wilcoxon paired sample test
Definition
 - differences in the central tendency of two paired samples of ratio-interval scale data when the normality assumption is not met- ordinal-scale data- calculated test stat uses n (sample size)
Term
 logarithmic transformation
Definition
 x' = log xconsistent (most common)
Term
 square root transformation
Definition
 x' = rad x whole number counts
Term
 arcsine square root transformation
Definition
 x' = arcsin rad x when data are proportions or percents
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