Ap Stats Unit 2 Vocab

Question 1

Sample

Answer 1

(Sum of all the Items in Sample) / (Number of Items in Sample - 1)

Question 2

Fractiles

Answer 2

numbers that partition, or divide, an ordered data set into equal parts

Question 3

Frequency Distributions

Answer 3

a table that shows classes or intervals of data entries with a count of the number of entries in each class

Question 4

Relative Frequency

Answer 4

the portion or percentage of the data that falls into that class

(Class Frequency) / (Sample Size) = f/n

Question 5

Cumulative Frequency

Answer 5

the sum of the frequencies of that class and all the previous classes

Question 6

Univariate Data Set

Answer 6

a data set consisting of observations on a single variable

Can be categorical (qualitative) if each observation is a categorical response

Can be numerical (quantitative) if each observations is a number

Question 7

Multivariate Data Set

Answer 7

a category or value of each of two or more attributes

Question 8

Continuous Data

Answer 8

a numerical variable whose possible values form an entire interval on a number line; it has an uncountable number of possible outcomes

Question 9

Pie Graph

Answer 9

A circle that is divided into sectors that represent categories

The area of each sector is proportional to the frequency of each category

Question 10

Steam-and-Leaf Plot

Answer 10

Each number is separated into a stem and leaf

Question 11

Paired data sets

Answer 11

when each entry in one data set corresponds to one entry in a second data set

Question 12

Weighted Mean

Answer 12

The mean of a data set whose entries have varying weights

Question 13

Symmetric

Answer 13

a vertical line can be drawn through the middle of a graph creating mirror images

Mean = Median = Mode

Question 14

Uniform (rectangular)

Answer 14

all entries, or classes, in the distribution have equal or approximately equal frequencies (symmetric)

Mean = Median = Mode

Question 15

Population Mean

Answer 15

(Sum of all items) / (Number of items)

Question 16

Quartiles

Answer 16

a division of data set into four equal parts

Question 17

Interquartile Range (IQR)

Answer 17

a measure of variation that gives the range of the middle 50% of the data

it is the difference between the third and first quartiles

Question 18

Fences

Answer 18

scores used to determine presence of outliers

Question 19

Frequency (f)

Answer 19

the number of data entries in the class

Question 20

Upper Class Limit

Answer 20

the greatest number that can belong to the class

Question 20

Lower Class Limit

Answer 20

the least number that can belong to the class

Question 21

Class Width (Class Interval)

Answer 21

the distance between lower (or upper) limits of consecutive classes

(Largest data value - smallest data value)/(Desired number of classes)

ALWAYS ROUND UP!!!!!

Question 22

Range

Answer 22

the difference between the max and min data entries

the data must be quantitative

Question 23

Midpoint

Answer 23

the sum of the lower and upper limits of the class divided by two (sometimes called the class mark)

(Lower class limit + Upper class limit)/2

Question 23

Frequency Histogram

Answer 23

A histogram that displays the data of a frequency distribution

Question 24

Bivariate Data Set

Answer 24

a data set consisting of observations for two variables Can be written as ordered pairs

Question 25

Discrete Data

Answer 25

a numerical variable whose possible values correspond to isolate points on a number line; it has a finite or countable number of possible outcomes

Question 26

Bar Graph

Answer 26

display for categorical data where the horizontal axis is categorical and the vertical axis is frequency

Question 26

Comparative Bar Chart

Answer 26

constructed by using the same horizontal and vertical axis for the bar charts of two or more groups

Question 27

Segmented Bar Chart

Answer 27

The bar is divided into segments, with different segments representing different categories

Question 28

Stem

Answer 28

the entry's left-most digit(s)

Question 29

Leaf

Answer 29

the entry's right-most digit (Laves should always be single digits)

Question 30

Outlier

Answer 30

an unusually small or large data value

Question 31

Gaps

Answer 31

spacing in the data set caused by one or more outliers

Question 31

Dot Plot

Answer 31

data points are plotted on a graph with a horizontal axis

Question 32

Scatter Plot

Answer 32

Ordered pairs are graphed as points in a coordinate plane Used to show the relationship between two quantitative variables

Question 33

Time Series

Answer 33

A data set that is composed of quantitative entries taken at regular intervals over a period of time

Question 33

Time Series Chart

Answer 33

A chart composed of a time series data set

Question 34

Median

Answer 34

The value that lies in the middle of the data when the data set is ordered If the data set has an odd number of entries, the median is the middle number If the data set has an even number of entries, the median is the mean of the two middle entries

Question 34

Measure of Central Tendency

Answer 34

a value that represents a typical, or central, entry of a data set Most commonly used are the mean, median and the mode

Question 34

Mode

Answer 34

The data entry that occurs with the greatest frequency

Question 35

Mean

Answer 35

the sum of the data entries divided by the number of entries

Question 36

Unimodal

Answer 36

a histogram with a single peak (one mode)

Question 36

Multimodal

Answer 36

a histogram with more than two peaks

Question 36

Skewed Left (negatively)

Answer 36

he tail extends left Mean < Median < Mode

Question 37

Bimodal

Answer 37

when two entries occur with the same greatest frequency a histogram with two peaks (two modes)

Question 37

Skewed Right (positively)

Answer 37

the tail extends to the right Mode < Median < Mean

Question 38

Sum of Squares

Answer 38

adding the squares of the deviations

Question 38

Deviation

Answer 38

The different between the entry and the mean of the data set

Question 38

Population Variance

Answer 38

the mean of the squares of the deviations

Question 39

Population Standard Deviation

Answer 39

the square root of the population variance

Question 40

The Empirical Rule (68-95-99.7 Rule)

Answer 40

For the data with a symmetric, bell shaped distribution, the standard deviation has the following characteristics: About 68% if the data lie within one standard deviation of the mean About 95% if the data lie within two standard deviations of the mean About 99.7% if the data lie within three standard deviations of the mean