STAT Ch 1

Question 0

Population

Answer 0

a well-defined collection of objects

Question 1

Data

Answer 1

collections of facts

Question 2

Census

Answer 2

When desired information is available for all objects in the population

Question 3

Sample

Answer 3

a subset of the population

Question 4

Variable

Answer 4

any characteristic whose value may change from one object to another

Question 5

univariate data set

Answer 5

consists of observations on a single variable. For example, we might determine the type of transmission, automatic (A) or manual (M), on each of ten automobiles recently purchased at a certain dealership, resulting in the categorical data set: M A A A M A A M A A

Question 6

bivariate data

Answer 6

when observations are made on each of two variables

Question 7

Multivariate data

Answer 7

when observations are made on more than one variable

Question 8

descriptive statistics

Answer 8

summarizing and describing important features of the data e.g. A graph or a mean

Question 9

Inferential statistics

Answer 9

Techniques for generalizing from a sample to a population

Question 10

hypothetical population

Answer 10

the population as consisting of all possible data that might be made under similar experimental conditions

Question 11

confidence interval or interval estimate

Answer 11

Estimate of the population mean

Question 12

lower prediction bound

Answer 12

Estimate of a single data point

Question 13

The relationship between probability and inferential statistics

Answer 13

probability reasons from the population to the sample (deductive reasoning), whereas inferential statistics reasons from the sample to the population (inductive reasoning)

Question 14

Enumerative studies

Answer 14

interest is focused on a finite, identifiable, unchanging collection of individuals or objects that make up a population

Question 15

Sampling frame

Answer 15

a listing of the individuals or objects to be sampled

Question 16

Analytic study

Answer 16

A study that is not enumerative in nature

Question 17

simple random sample

Answer 17

This is a sample for which any particular subset of the specified size (e.g., a sample of size 100) has the same chance of being selected

Question 18

stratified sampling

Answer 18

entails separating the population units into nonoverlapping groups and taking a sample from each one

Question 19

Sample size

Answer 19

The number of observations in a single sample, often denoted by “n”

Question 20

Truncating

Answer 20

To make the numbers in a set all shorter by the same amount

Question 21

Dot plot

Answer 21

an attractive summary of numerical data when the data set is reasonably small or there are relatively few distinct data values. Each observation is represented by a dot above the corresponding location on a horizontal measurement scale. Whena value occurs more than once, there is a dot for each occurrence, and these dots are stacked vertically. As with a stem-and-leaf display, a dotplot gives information about location, spread, extremes, and gaps.

Question 22

Discrete

Answer 22

A numerical variable is called this if its set of possible values either is finite or else can be listed in an infinite sequence

Question 23

Continuous

Answer 23

A numerical variable is called this if its possible values consist of an entire interval on the number line.

Question 24

Frequency

Answer 24

the number of times that a value occurs in the data set

Question 25

Relative frequency

Answer 25

the fraction or proportion of times the value occurs ( number of times the value occurs/ the number of observations in the data set)

Question 26

Frequency distribution

Answer 26

a tabulation of the frequencies and/or relative frequencies

Question 27

unimodal histogram

Answer 27

A histogram that rises to a single peak and then declines

Question 28

bimodal histogram

Answer 28

A histogram that has two different peaks

Question 29

multimodal

Answer 29

A histogram with more than two peaks

Question 30

When is a histogram symmetric?

Answer 30

if the left half is a mirror image of the right half

Question 31

When is a unimodal histogram positively skewed?

Answer 31

if the right or upper tail is stretched out compared with the left or lower tail

Question 32

When is a unimodal histogram negatively skewed?

Answer 32

if the left or lower tail is stretched out compared with the right or upper tail

Question 33

qualitative

Answer 33

Categorical

Question 35

Mean

Answer 35

The arithmetic average of the set. Often referred to as the sample mean and represented by x̄.

Question 35

point estimate

Answer 35

a single number that is our “best” guess

Question 36

Population mean

Answer 36

The average of all values in the population. Denoted as μ. When there are N values in the population (a finite population), then μ= sum of the N population values/N.

Question 38

median

Answer 38

the middle value once the observations are ordered from smallest to largest. Sample median is denoted as x-tilde

Question 38

Range

Answer 38

the difference between the largest and smallest sample values

Question 39

population median

Answer 39

a middle value in the population. Denoted as μ-tilde

Question 41

deviations from the mean

Answer 41

Obtained by subtracting x̄ from each of the n sample observations. The average deviation is always zero.

Question 42

sample variance

Answer 42