Final Terms

Question 1

observational study

Answer 1

researchers simply observe characteristics and take measurements, as in a sample survey; reveal association

Question 2

designed experiment

Answer 2

researchers impose treatments and controls and then observe characteristics and take measurements; establish casuality

Question 3

sample

Answer 3

a portion, or part, of the population of interest; often used to obtain reliable estimates of population parameters

Question 4

population

Answer 4

the entire set of individuals or objects of interest of the measurements obtained from all individuals or objects of interest

Question 5

nominal level of measurement

Answer 5

Data recorded is represented as labels or names. They have no order. They can only be classified and counted. EX: gender, races, states

Question 6

ordinal level of measurement

Answer 6

Data recorded is based on a relative ranking or rating of items based on a defined attribute or qualitative variable. Variables based on this level of measurement are only ranked or counted. EX: top 10 us universities

Question 7

interval level of measurement

Answer 7

the interval or distance between values in the data is meaningful. The interval level of measurement is based on a scale with a known unit of measurement. Addition and subtraction can be performed on these values. EX: temperature

Question 8

ratio level of measurement

Answer 8

data recorded is based on a scale with a known unit of measurement and a meaningful interpretation of zero on the scale (0 means absence of quantity). EX: length, weight, distance, age

Question 9

random sampling

Answer 9

the process of using chance to select individuals from a population to be included in the sample

Question 10

simple random sample

Answer 10

a sample selected so that each item or person in the population has the same probability or chance of being selected

Question 11

systematic random sampling

Answer 11

a random starting point is selected, and then every kth member of the population is selected. The first individual selected corresponds to a random number between 1 and k

Question 12

stratified random sampling

Answer 12

a population is divided into subgroups, called strata, and a sample is randomly selected from each stratum

Question 13

cluster sampling

Answer 13

a population is divided into clusters using naturally occurring geographic or other boundaries. They are randomly selected and a sample is collected by randomly selecting from each cluster

Question 14

k

Answer 14

population/sample size

Question 15

frequency table

Answer 15

a grouping of qualitative data into mutually exclusive and collectively exhaustive classes showing the number of observations in each class

Question 16

relative frequency

Answer 16

ratio of the frequency to the total number of observations (frequency/sum of all frequencies)

Question 17

classes

Answer 17

categories into which data is grouped

Question 18

class frequency

Answer 18

number of observations in each class

Question 19

variance

Answer 19

the mean of the squared deviations from the mean

Question 20

mutually exclusive

Answer 20

the occurrence of one event means that none of the other events can occur at the same time

Question 21

collectively exhaustive

Answer 21

at least one of the events must occur when an experiment is conducted.

Question 22

law of large numbers

Answer 22

over a large number of trials, the empirical probability of an event will approach its true probability

Question 23

contingency table

Answer 23

a table used to classify sample observations according to two or more identifiable categories or classes