PAIx Lab 3- Investigating Spatial Patterns of Populations

Question 1

what is a quadrent bsed sampling tehnique

Answer 1

Sample smaller areas of the habiat that represent tne habitat as a whole

Question 2

what are spatial patterns

Answer 2

• Spatial patterns may be both causes and consequences of multiple processes

Question 3

selection methofd for location

Answer 3

random, regular, stratified random

Question 4

random

Answer 4

• Random: 1) every point in a study area has an equal probability of being in the sample and 2) the location of one samp does not influence the location of any other sample

Question 5

stratified random

Answer 5

• Stratified random: condtion 1 of random is fulfilled, but samples are spread throughout study. placement of one sample eliminates the possibility of another being located in the same grid square

Question 6

regular

Answer 6

• Regular: smaples placed at regular intervals along a line or interscting pints of line grid

Question 7

basic dispersion patterns

Answer 7

• Basic dispersion patterns: uniform, clumped, or random. Generally is clumped

Question 8

probability distributions

Answer 8

• Proability distributions: normal, chi-square, binomial, poisson

Question 9

poisson distribution

Answer 9

• Poisson distrubution helps describe the chances of occurance of a number of events in some give time interval or given space conditionally that the value of avergae number of occurances of the event is known

Question 10

if mean=variance

Answer 10

• Mean= variance, observed distribution matches the distribution expected unde rthe poisson probability density function

Question 11

if mean> variance

Answer 11

• Mean > variance: observed distribution is tending toward unifrom. More quadrents will have values close to the mean

Question 12

if mean < variance

Answer 12

• Mean < variance: observed distribution is tending towards clumped. Hisrogram with very long tails, l[ossibly u shaped

Question 12

what is VMR

Answer 12

• VMR: index of dispersion
• Used to characterize the distribution of events or objects in time or spacem and is a good measure of degrese of randomness

Question 13

what does ratio near 1 mean

Answer 13

• Ration near 1 indicated random distribution

Question 14

what ration much less than 1 indicate

Answer 14

• Raion much less than 1 indicates uniform distribution

Question 15

what does a raio much greater than 1 indicate

Answer 15

• Ratio much greater than 1 indicated clumpsed distribution

Question 16

what is chi- square method

Answer 16

• Chi square: method for determining significant departure from randomness uses the chi square statistic
• Used to calculate the expected value from a data set that has observed values
• Tests validaty of hypothesis
• P values tells if signifcant