chapter 1

Question 1

observational study

Answer 1

measures the cvaule of the response variable without attempting to influence the vaule of either the response or explanitory variable. That is, in an observational study, the researcher observes the behaivor of the individual without trying to influence the outcome of the study.

Question 2

Designed experiment

Answer 2

if a reseacher assigns the individual in a study to a certian group, intionally changes the vaule of an explanatory variable, and then records the vaule of the response variable for each group

Question 3

Stratified sample

Answer 3

is obtained by seperating the population into nonoverlapping groups caled strata and then obatianing a simple random sample from each stratum. The individuals within each stratum should be homogenous ( or similar) in some way.

Question 4

systematic system

Answer 4

s obtained by selecting ever kth individual from the population. the first individual selected corresponds to a random number between 1 and k.

Question 5

cluster sample

Answer 5

is obtained by slecting all the indivduals with a randomly selected collection otr group of individual.

Question 6

convencience

Answer 6

is a sample in which the individuals are easily obtained and not on based randoms

Question 7

Sampling bias

Answer 7

means that the technique used to obtain the samples of individuals tends to favor one point of the populationover another

Question 8

nonresponse bias

Answer 8

exists when individual selected to be in the sample who do not respond to the survey different opinions from those who do.

Question 9

Response Bias

Answer 9

Exist when the answers on a survey do not reflect the true feelings of the respondent

Question 10

statistics

Answer 10

is the science of collecting, organizing, summarizing, and analyzing information to draw a conclusions or answers questions. In addition, statistics is about providing a measure of confidence in any conclusion.

Question 11

Qualitative or categorical , variables

Answer 11

allows for classification of individuals based on a some attribute or characteristic

Question 12

Quantative variable

Answer 12

provide numerical measurements of individuals. The values of a quantative varaible can be added or subtrated and provide meaniful results

Question 13

Discrete variable

Answer 13

is a quantative variable that has either a finite number of possible values or a countable number of possible values. The term countable means that the values result from counting, such as 0,1,2,3 and so on. A DISCRETE VARAIBLE CANNOT TAKE ON EVERY POSSIBLE VALUE BETWEEN ANY TWO POSSIBLE VALUES.

Question 14

Continuous variable

Answer 14

is a quantatative variable that has an infinite number of possible values that are not countable. A contious varaible may take every possible betwwen any two values

Question 15

nominal

Answer 15

if the values of the variable name, label, or categorized. NO SPECIFIC ORDER.

Question 16

Ordinal

Answer 16

if it has the properties of the nominal level of measurement, however the naming scheme allows for the values of the variable to be arranged in a ranked or specific order.

Question 17

internal

Answer 17

if it has the properties of the ordinal level and the difference in the values of the variable have meaning. A value of zero does not mean the abscence of the quantity. Arthimetic operations such as addition and subtration can be performed on values of the variable.

Question 18

Ratio

Answer 18

Prperties of the interval and the ratios of the values have meaning. Avalue of zero means the abscence of quantity. Arhtimitc operations such as multiplecation and division can be performed on the values of the variable.

Question 19

Parameter

Answer 19

is a nemericasl summeray of population

Question 20

confounding

Answer 20

in a study occurs when the effects of two or more explanatory variables are not seperated. Therefore, any relation that may exist between an explantory.

Question 21

Lurking Variable

Answer 21

is an explanatory varaible that was not considered in a study, but the affects the value of the response variable in the study. In addition, the lurking varaibles are typically related to the explantory variable

Question 22

cross -sectional

Answer 22

are observations studies that collect information about individuals, at a specific point in time or over long period of time

Question 23

case-control study

Answer 23

are observational studies that are retrospective, meaning that they require individuals to look back in time or require the research to look at existing records.