stats final

Question 1

t-test variables

Answer 1

independent: categorical w/ 2 levels
dependent: numerical

Question 2

ANOVA variables

Answer 2

independent: categorical w/ 3+ levels
dependent: numerical

Question 3

paired t-test variables

Answer 3

independent: categorical w/ 2 levels
dependent: numerical
there must be equal numbers in each category between the pair

Question 4

Chi-Squared variables

Answer 4

independent: categorical w 2+ levels
dependent: categorical w 2+ levels

Question 5

linear regression variables

Answer 5

independent: numerical
dependent: numberical

Question 6

null hypothesis

Answer 6

independent variable has no effect on the dependent variable

Question 7

alternative hypothesis

Answer 7

independent variable has an effect on the dependent variable

Question 8

p-value

Answer 8

probability that the null is true, must be lower than 0.05/5% to reject null

Question 9

type 1 error

Answer 9

the chance of the probability that we reject the null when the null is true
equal to p-value

Question 10

stats relies on 2 fundamental ideas

Answer 10

uncertainty and variation

Question 11

random sampling

Answer 11

removes bias

Question 12

systematic sampling

Answer 12

transects, collect data while walking straight thru area, etc

Question 13

mixed/stratified sampling

Answer 13

taking samples randomly within certain sections of an overall space

Question 14

haphazard sampling

Answer 14

sampling whatever is accesible

Question 15

standard error of the mean

Answer 15

estimate of how close your sample mean is compared to the true population mean

Question 16

central limit theorem

Answer 16

if a population with finite variance is sufficiently sampled, the mean of all samples from population will be abt equal to the mean of the population and the means from the samples will approach a normal distribution

Question 17

descriptive test

Answer 17

dont carry out hypothesis, just describe situation
histograms, density plot, boxplot

Question 18

differences test

Answer 18

set out to compare 2 sets of data
barcharts and boxplots

Question 19

correlation/regression test

Answer 19

emphasis on linking variables
scatterplots and lineplots

Question 20

association

Answer 20

looking for links between variables that are categorical

Question 21

percentage of population that lies within 1.96 st dev of a normally distributed mean

Answer 21

95%

Question 22

% of population that lies within 1 st dev of the a normally distributed mean

Answer 22

68%

Question 23

how is standard error of the mean different than standard deviation

Answer 23

more precise, but not more accurate

Question 24

when is log normal distribution appropriate

Answer 24

positive skewed data

Question 25

sample standard deviation

Answer 25

square root of the average squared differences from the mean

Question 26

test done if ANOVA results are significant

Answer 26

tukey’s hsd test

Question 27

non parametric alt to ANOVA

Answer 27

kruskal-wallis test

Question 28

test done if kruskal wallis test is significant

Answer 28

dunn test

Question 29

non parametric alt to paired t-test

Answer 29

wilcoxon matched pairs test

Question 30

f-stat

Answer 30

group variance

Question 31

non parametric alt to 2-sample t-test

Answer 31

mann whitney u-test

Question 32

non parametric alt to correlation/regression

Answer 32

spearman’s rank test