statistics

Question 1

population

Answer 1

the entire set of individuals or objects of interest

Question 2

sample

Answer 2

a portion, a selected part, of the population

Question 3

individuals

Answer 3

the minimum unit that can be studied

Question 4

statistic

Answer 4

an approximation to the parameter, that can be calculated from our data

Question 5

simple random (probability) sampling

Answer 5

random numbers form 1 - N

Question 6

cluster (probability) sampling

Answer 6

simple random sampling of clusters

Question 7

stratified (probability) sampling

Answer 7

• order population in strata
• simple random sampling in the strata
• these might have different sample sizes (or not)

Question 8

convenience (non-probability) sampling

Answer 8

when units are selected for inclusion in the sample because they are the easiest for the researcher to access

Question 9

snowball (non-probability) sampling

Answer 9

a recruitment technique in which research participants are asked to assist researchers in identifying other potential subjects.

Question 10

quota (non-probability) sampling

Answer 10

it relies on the non-random selection of a predetermined number or proportion of units.

Question 11

frequency

Answer 11

the number of observations for each group

Question 12

absolute frequencies

Answer 12

counting the observations

Question 13

relative frequencies

Answer 13

percentage (or fraction) of observations in each group

Question 14

measures of centrality

Answer 14

trying to summarize the data by identifying the central position of the data

Question 15

mean (or average)

Answer 15

the sum of the data divided by the number of observations

Question 16

median

Answer 16

midpoint of the values ordered in size

Question 17

mode

Answer 17

most frequent observation

Question 18

dispersion

Answer 18

informs about the variability in the data

Question 19

variance

Answer 19

a measurement of how far each number in a data set is from the mean, and thus from every other number in the set.

Question 20

standard deviation

Answer 20

a statistic that measures the dispersion of a dataset relative to its mean and it is calculated as the square root of the variance

Question 21

boxplot

Answer 21

univariate descriptives

Question 22

multivariate descriptive statistics

Answer 22

shows the relation between two or more variables, which can be of different types

Question 23

statistical inference

Answer 23

data analysis to study the underlying probability distribution

Question 24

hypothesis testing

Answer 24

an act in statistics whereby an analyst tests an assumption regarding a population parameter

Question 25

null hypothesis

Answer 25

a type of statistical hypothesis that proposes that no statistical significance exists in a set of given observations.

Question 26

false positive

Answer 26

an investigator rejects a null hypothesis that is actually true in the population. It is usually more problematic

Question 27

false negative

Answer 27

the investigator fails to reject a null hypothesis that is actually false in the population.

Question 28

probability (alpha)

Answer 28

statistical significance

Question 29

p-value

Answer 29

probability, under the null hypothesis, of sampling a test statistic at least as extreme as that which was observed

Question 30

low p-value

Answer 30

reject H0 and accept H1

Question 31

high p-value

Answer 31

cannot reject H0 and cannot accept H1

Question 32

homogeneity of contingency tables

Answer 32

when the distribution of observations in the rows (or in the columns) could be explained by random sampling of the observations in the columns (or rows)

Question 33

Shapiro-Wilk

Answer 33

normality test but only for n<50

Question 34

Kolmogorov-Smirnov

Answer 34

one sample vs a distribution, or two samples

Question 35

95% interval of confidence

Answer 35

has a 95% likelihood of containing the parameter value