question

What is voluntary response sample?

answer

A sample in which the subjects themselves decide whether to be included in the study.

question

Which of the following is typically the important factor to consider when conducting a statistical analysis of data?

answer

1. Sampling method
2. Context of the data
3. Source of the data

question

What does it mean for the findings of a statistical analysis of data to be statistically significant?

answer

The likelihood of getting these results by chance is very small.

question

Sampling method

answer

If we are collecting sample data for a study, the _ that we choose can greatly influence the validity of our conclusions. For example, we can use sound statistical methods to analyze data in voluntary response samples, but the results are not necessarily valid.

question

How do parameter and statistic differ?

answer

A parameter is a numerical measurement of a population; a statistic is a numerical measurement of a sample.

question

Which of the following is associated with a parameter?

answer

Data that were obtained from an entire population.

question

Why is a voluntary response sample generally unsuitable for methods of statistics?

answer

People with special interests are more likely to respond, so the sample is likely to be biased.

question

What is the goal of learning statistics?

answer

To learn to distinguish between statistical conclusions that are likely to be valid and those that are seriously flawed.

question

What is a self-interest study?

answer

A survey in which the sponsor can enjoy monetary or other gains from the results.

question

What is the difference between a random sample and a simple random sample?

answer

With a random sample, each individual has the same chance of being selected. With a simple random sample, all samples of the same size have the same chance of being selected.

question

Which sampling method divides the population up into sections, randomly selects some of those sections, then choose all the members from the selected sections to study?

answer

Cluster

question

Which sampling method subdivides the population into categories sharing similar characteristics and then selects a sample from each subdivision?

answer

Stratified

question

Randomization

answer

_is used when subjects are assigned to different groups through a process of random selection.

question

Which of the following corresponds to the case when every sample of size n has the same chance of being chosen?

answer

Simple random sample

question

Which characteristic of data is a measure of the amount that the data values vary?

answer

Variation

question

Outliers

answer

_are sample values that lie very far away from the majority of the other sample values.

question

Frequency distribution

answer

A frequency distribution helps us understand the nature of the distribution of a data set.

question

Class width is found by

answer

subtracting a lower class limit from the next consecutive lower class limit

question

relative frequency

answer

In a relative frequency distribution, the frequency of a class is replaced with a proportion or percent.

question

frequency

answer

The heights of the bars of a histogram correspond to frequency values.

question

touch

answer

The bars in a histogram touch.

question

shape of the distribution

answer

A histogram aids in analyzing the _ of the data.

question

relative frequency

answer

A _ histogram has the same shape and horizontal scale as a histogram but the vertical scale is marked with relative frequencies instead of actual frequency.

question

normal

answer

A(n)_distribution has a "bell" shape.

question

What are some advantages of a dotplot over a frequency polygon

answer

A dotplot allows you to identify the original data values.

question

frequency polygon

answer

A(n)_uses line segments to connect points located directly above class midpoint values.

question

dotplot

answer

A_is a graph of each data value plotted as a point.

question

graphs

answer

We utilize statistical _ to look for features that reveal some useful or interesting characteristics of the data set.

question

scatterplot

answer

A _ is a plot of paired data (x,y) and is helpful in determining whether there is a relationship between the two variables.

question

a nonzero axis

answer

In a graph, if one or both axes begin at some value other than zero, the differences are exaggerated. This bad graphing method is known as _

question

pictographs

answer

When drawings of objects are used to depict data, false impressions can be made. These drawings are called _

question

Which of the following is a common distortion that occurs in graphs

answer

Using a two-dimensional object to represent data that are one-dimensional in nature.

question

Why is it important to learn about bad graphs?

answer

So that we can critically analyze a graph to determine whether it is misleading.

question

descriptive

answer

Methods used that summarize or describe characteristics of data are called _ statistics.

question

measure of center

answer

A value at the center or middle of a data set is a(n) _

question

mode

answer

The measure of center that is the value that occurs with the greatest frequency is the _

question

Range

answer

The measure of variation that is very sensitive to extreme values

question

s=range/4

answer

The Range Rule of Thumb roughly estimates the standard deviation of a data set as _

question

the Empirical Rule

answer

For data sets having a distribution that is approximately bell-shaped, _ states that about 68% of all data values fall within one standard deviation from the mean.

question

variance

answer

The square of the standard deviation is called the_

question

z-score

answer

When a data value is converted to a standardized scale representing the number of standard deviations the data value lies from the mean, we call the new value a _

question

unusual

answer

A data value is considered _ if its z-score is less than -2 or greater than 2

question

the corresponding z-score is negative

answer

Whenever a data value is less than the mean, _

question

outlier

answer

In modified boxplots, a data value is a(n) outlier if it is above Q3+(1.5)(IQR) or below Q1-(1.5)(IQR).

question

sample space

answer

The _ for a procedure consists of all possible simple events or all outcomes that cannot be broken down any further.

question

equally likely

answer

The classical approach to probability requires that the outcomes are _

question

the law of large numbers

answer

As a procedure is repeated again and again, the relative frequency of an event tends to approach the actual probability. This is known as _

question

actual odds in favor of

answer

The _ event A occurring are the ratio P(A)/(P(A-)

question

addition rule

answer

When using the _ always be careful to avoid double-counting outcomes.

question

disjoint

answer

Events that are _ cannot occur at the same time

question

rule of complementary events

answer

P(A) + P(A-) = 1 is one way to express the _

question

P(A or B) indicates

answer

the probability that in a single trial, event A occurs, event B occurs, or they both occur.

question

compound event

answer

A _ is any event combining two or more simple events.

question

Describe what the notation P(BlA) represents.

answer

The probability of event B occurring, given that event A has already occurred.

question

tree diagram

answer

A picture of line segments branching out from one starting point illustrating the possible outcomes of a procedure is called a _

question

independent

answer

Two events A and B are _ if the occurrence of one does not affect the probability of the occurrence of the other.

question

independent

answer

Selections made with replacement are considered to be _

question

"one ore more"

answer

"At least one" is equivalent to_

question

"none"

answer

The complement of "at least one" is _

question

conditional

answer

A conditional probability of an event is a probability obtained with knowledge that some other event has already occurred.

question

P(BlA) = P(AlB)

answer

Confusion of the inverse occurs when we incorrectly believe _

question

assuming that event A has occurred, and then calculating the probability that event B will occur

answer

The conditional probability of B given A can be found by _