Flashcards in statistics exam 1 Deck (53):

1

## the basic unit of an experiment upon which the treatment is applied.

### individual

2

## An experimental condition where neither the subjects nor the diagnosticians (doctor, nurse, etc) know which treatment each subject received.

### double blind

3

## a weakness in experiments where the setting of the experiment does not realistically duplicate the conditions we really want to study.

### lack of realism

4

## an experimental design where all individuals are assigned at random to treatments

### completely randomized

5

## a study in which treatments are imposed on the individuals before responses are measured.

### experiment

6

## the grouping of individuals according to some similar characteristics. The random allocation is carried out separately within each group.

### Blocking

7

## A treatment where either no experimental condition or a placebo treatment is applied to the individuals in order to determine whether the active treatment works. This together with randomization enables the researcher to "control" lurking variables.

### control

8

## A study in which data are gathered without imposing treatments on the individuals.

### observational study

9

## A variable that is studied to determine whether it affects the outcomes of a study.

### explanatory variable

10

## A variable that has an effect on the response variable but is not included as one of the variables in a study.

### lurking variable

11

## the response of patients to any treatment that has no physical effect.

### placebo effect

12

## a method of assigning individuals to treatment groups that eliminates bias and gives each unit the same probability of being assigned to any treatment group.

### randomization

13

## results of a study that differ too much from what we expected because of randomization to attribute to chance.

### statistically significant

14

## a situation where the effect of one variable on the response variable cannot be separated from the effect of another variable on the response variable.

### confounding

15

## The application all the treatment combinations to more than one individual within an experiment

### replication

16

## Type of sampling required for inference.

### sample selected with some type of random device

17

## Using results from a sample to draw conclusions about the entire population.

### inference

18

## A sampling scheme where the population has been divided into strata according to some characteristic and a simple random sample is selected from each stratum.

### stratified sample

19

## A sample selected in such a way that the probability of each possible sample of size n has a known chance of being selected.

### probability sample

20

## A method of sample selection that consists of people choosing themselves by responding to a general appeal.

### voluntary response sample

21

## A condition that occurs when the design of a study systematically favors certain outcomes.

### bias

22

## The entire group of individuals about whom we desire to collect information.

### population of interest

23

## A subgroup of the population that we actually examine and about whom we gather information

### sample

24

## A sample of size n selected from the population in such a way that every possible sample of size n has an equally likely chance of being selected.

### simple random sample

25

## A sample type where the researcher contacts those subjects who are readily available and does not use any random selection.

### convenience sample

26

## An observation that falls outside the overall pattern of the data set.

### outlier

27

## measure for the center of the data that "balances" the data.

### mean

28

## a measure of the center of data that splits the ordered data in half.

### median

29

## A location measure of the data that has approximately one fourth or 25% of the data below it.

### Q1

30

## A location measure of the data that has approximately one fourth or 25% of the data above it.

### Q3

31

## s

### sample standard deviation

32

## r

### correlation coefficient

33

## n

### sample size

34

## A representative measure of the deviations of the data about the mean

### standard deviation

35

## maximum observation minus the minimum observation

### range

36

## A measure of the "average" or typical deviation of the observations about the mean.

### standard deviation

37

## The difference between the third quartile and the first quartile.

### IQR, interquartile range

38

## the measure of variability that should be used for strongly skewed data or data with outliers.

### interquartile range

39

## A curve that is mound shaped symmetric used to model data from measurements on animal species.

### Normal Distribution

40

## A normal distribution that has a mean of zero and a standard deviation of one.

### standard normal distribution

41

## A measure of the number of standard deviations of a value or observation from the mean.

### z-score

42

## In a normal distribution, the percentages of values that are within on e standard deviation of the mean.

### 68%

43

## In a normal distribution, the percentage of values that are within two standard deviations of the mean.

### 95%

44

## A graph for categorical data

### bar graph

45

## A plot of data that incorporates the maximum observation, the minimum observation, the first quartile, the second quartile, and the third quartile.

### boxplot

46

## A distribution where the left side of the distribution extends in a long tail.

### left skewed

47

## A list of the possible values of a variable together with the frequencies of each value.

### distribution

48

## The shape of a distribution where the mean exceeds the median.

### right skewed

49

## A plot used to provide a picture of one variable quantitative data.

### stemplot, dotplot, histogram, or boxplot

50

## The shape of a histogram where the median exceeds the mean.

### left-skewed

51

## The shape of a histogram where the mean equals the median.

### symmetric

52

## The recommended plot for displaying small quantitative data sets

### stemplot

53