1St Semester Exam Stats In Action 1St Ed

Front 1

AVERAGE

Back 1

(i) The (arithmetic) mean (ii) Any measure of central tendency

Front 2

BAR CHART or BAR GRAPH

Back 2

A graphical method of presenting data. A plot that shows frequencies for categorical data as heights or lengths of bars, with one bar for each category.

Front 3

BIAS

Back 3

A sampling method is biased if each element does not have an equal chance of being selected. A sample of internet users found reading an online statistics book would be a biased sample of all internet users. A random sample is unbiased. Note that possible bias refers to the sampling method, not the result. An unbiased method could, by chance, lead to a very non-representative sample.

Front 4

BIAS

Back 4

An estimator is biased if it systematically overestimates or underestimates the parameter it is estimating. In other words, it is biased if the mean of the sampling distribution of the statistic is not the parameter it is estimating, The sample mean is an unbiased estimate of the population mean. The mean squared deviation of sample scores from their mean is a biased estimate of the variance since it tends to underestimate the population variance

Front 5

BIMODAL DISTRIBUTION

Back 5

A distribution with two distinct peaks

Front 6

BIN WIDTH

Back 6

Also known as the class interval, the bin width is a division of data for use in a histogram.For instance, it is possible to partition scores on a 100 point test into class intervals of1-25, 26-49, 50-74 and 75-100.

Front 7

BIVARIATE DATA

Back 7

Data that involve two variables per case. For quantitative variables, often displayed on a scatterplot. For categorical variables, often displayed in a two-way table.

Front 8

BOX PLOT

or Box-and-whisker plot

Back 8

A graphical display of the five-number summary. The "box" extends from the lower quartile (Q1) to the upper quartile (Q3), with a line across it at the median (Q2). The "whiskers" run from the quartiles to the minimum or maximum.

Front 9

CLASS FREQUENCY

Back 9

One of the components of a histogram, the class frequency is the number of observations in each class interval.

Front 10

CENTRAL TENDENCY

Back 10

There are many measures of the center of a distribution. These are called measures of central tendency. The most common are the mean, median, and, mode.

Front 11

CLASS INTERVAL

Back 11

Also known as bin width, the class interval is a division of data for use in a histogram. For instance, it is possible to partition scores on a 100 point test into class intervals of 1-25, 26-49, 50-74 and 75-100

Front 12

CONFOUNDING

Back 12

Two or more variables are confounded if their effects cannot be separated because they vary together. For example, if a study on the effect of light inadvertently manipulated heat along with light, then light and heat would be confounded

Front 13

CUMULATIVE FREQUENCY DISTRIBUTION

Back 13

A distribution showing the number of observations less than or equal to values on the X-axis. The following graph shows a cumulative distribution for scores on a test

Front 14

DESCRIPTIVE STATISTICS

Back 14

1. The branch of statistics concerned with describing and summarizing data. 2.A set of statistics such as the mean, standard deviation, and skew that describe a distribution.

Front 15

DEVIATION SCORES

Back 15

Scores that are expressed as differences (deviations) from some value, usually the mean. To convert data to deviation scores typically means to subtract the mean score from each other score. Thus, the values 1, 2, and 3 in deviation-score form would be computed by subtracting the mean of 2 from each value and would be -1,0, 1.

Front 16

BLIND

Back 16

A type of experiment in which the subjects do not know which treatment they received.

Front 17

BLOCKS

Back 17

In an experiment, groups of similar units.

Front 18

DISTRIBUTION

Back 18

The distribution of empirical data is called a frequency distribution and consists of a count of the number of occurrences of each value. If the data are continuous, then a grouped frequency distribution is used. Typically, a distribution is portrayed using a frequency polygon or a histogram. Mathematical equations are often used to define distributions. The normal distribution is, perhaps, the best known example. Many empirical distributions are approximated well by mathematical distributions such as the normal distribution

Front 19

CASE

Back 19

The subject (or object) on which a measurement is made in statistical examination.

Front 20

CATEGORICAL VARIABLE

Back 20

A variable that can be grouped into categories, such as “yes” and “no.” Categories sometimes can be ordered as with “small,””medium,” and “large.”

Front 21

CENSUS

Back 21

An examinationof all individuals in the entire population.

Front 22

CLINICAL TRIAL

Back 22

A randomized experiment comparing medical treatments.

Front 23

CLUSTER

Back 23

On a plot, a group of data “clustering” close to the same value, away from other groups.

Front 24

CLUSTER SAMPLING

Back 24

When the units in the population are assigned to clusters (such as classrooms) and you take a simple random sample of the clusters.

Front 25

COEFFICIENT OF DETERMINATION

Back 25

the square of the correlation r. Tells the proportion of the total variation in y that can be explained by the relationship with x.

Front 26

COMPARISON GROUP

Back 26

In an experiment, a group that receives one of the treatments, often the standard treatment.

Front 27

COMPLETELY RANDOMIZED DESIGN

Back 27

An experimental design in which treatments are randomly assigned to subjects with restriction.

Front 28

CONFOUNDING

Back 28

The phenomenon that occurs when an experimental design has mixed together two possible influences on a response in such a way that it is impossible to separate their effects.

Front 29

CONTINUOUS VARIABLE

Back 29

A quantitative variable that can take on any value on an interval of real numbers.

Front 30

CONTROL GROUP

Back 30

In an experiment, a group that provides a standard for comparison to evaluate the effectiveness of a treatment; often given the placebo.

Front 31

CONVENIENCE SAMPLE

Back 31

A sample in which the units chosen from the population are the units that are easy to conclude.

Front 32

CORRELATION

Back 32

A numerical value between -1 and 1 inclusive that measures the strength and direction of a linear relationship between two variables.

Front 33

DATA

Back 33

A set of numbers or observations with a context and drawn from a real-life situation.

Front 34

DOT PLOT

Back 34

A graphical display that shows the values of a variable along a number line.

Front 35

DOUBLE-BLIND

Back 35

A type of experiment in which neither the subjects nor the research making eh measurements knows which treatment the subjects receive.

Front 36

FREQUENCY (or COUNT)

Back 36

The number of times a value occurs in the distribution.

Front 37

FREQUENCY TABLE

Back 37

A table that gives the values and their frequencies (counts).

Front 38

HISTOGRAM

Back 38

A plot for quantitative variables that groups cases into rectangles or bars. The height of the bar shows the frequency.

Front 39

INCORRECT RESPONSE BIAS

Back 39

A bias resulting from responses that systematically wrong, such as from intentional lying, inaccurate measurement devices, or faulty memories.