Chapter 1 Behavioral Stats.

Data

A set of scores, measurements, or observations that are typically numeric

Datum

A single measurement or observation, usually referred to as a score or raw score

Σ

sum

Data from airline passengers were ranked by their country of origin, an example of a: a) nominal scale b) ordinal scale c) interval scale d) ratio scale

A

A librarian at a university is interested in looking at how many undergraduate students use the library. He records student use of different library resources and tabulates this usage. This information is an example of: a) descriptive statistics b) inferential statistics c) population d) parameter

A

experimental method

A method of investigation used to demonstrate cause-and-effect relationships by purposely manipulating one factor thought to produce change in another factor.

Continuous Variable

A variable measured along a continuum at any place beyond the decimal point. A continuous variable can thus be measured in fractional units

A librarian at a university is interested in looking at how many undergraduate students use the library. He records student use of different library resources in one month and extrapolates this information for the year-round usage. This is an example of: a) descriptive statistics b) inferential statistics c) population d) parameter

B

A librarian at a university is interested in looking at how undergraduate students use the library resources. He sends a survey about the library usage to all undergraduate students in the college but receives responses from only a subset of students. In this example, the librarian was interested in getting information from the ______, but could obtain only a ______. a) descriptive; inferential b) population; sample c) sample; population d) parameter; statistic

B

In blinded studies, consumers' rankings of the effectiveness of brand name painkillers did not differ from generic painkillers that had the same key ingredients, on a 5-point scale. The scale used in these studies is: a) a nominal scale b) an interval scale c) an ordinal scale d) a ration scale

B

Is children's vocabulary related to their parents' education level? To answer this, researchers measured the number of words 3-year-old children knew and their parents' education (in number of years). This data can be examined using: a) experimental method b) correlational method c) measurement d) quasi-experimental method

B

Randomly assigning to different groups to ensure that manipulations of the independent variable are measured on similar groups is necessary in: a) correlational method b) quasi-experimental method c) experimental method d) measurement

C

Students were asked to rate the effectiveness of video lectures for an online class. Their ratings on a 5-point scale would be: a) discrete and qualitative b) continuous and quantitative c) discrete and quantitative d) continuous and qualitative

C

A researcher studies the development of cognitive flexibility by testing children of different age groups on a problem-solving task. This is an example of a: a) experimental method b) measurement c) correlational method d) quasi-experimental method

D

Listeners to a specific radio station were asked to rank one hundred songs for popularity. The composite rank scores for the songs were then published and showed the use of a: a) interval scale b) nominal scale c) ratio scale d) ordinal scale

D

Descriptive statistics can help to infer the unknown parameters in a population. True/False

False

High School GPA and score on the SAT exams are considered during college admissions. Both these values are continuous and quantitative measurements. True/False

False

In an ordinal scale, a larger number represents a greater value than a smaller number, and the ratio of any two numbers represents a meaningful value. True/False

False

discrete variable

Measured in whole units or categories that are not distributed along a continuum

Descriptive Statistics

Procedures used to summarize, organize, and make sense of a set of scores called data. These are typically presented graphically, in tabular form, or as summary statistics

independent variable

The experimental factor that is manipulated; the variable whose effect is being studied.

Coding

The procedure of converting a nominal or categorical variable to a numeric value

Dependent Variable (DV)

The variable that is measured in each group of a study and is believed to change in the presence of the independent variable. It is the "presumed effect," so to speak

A continuous variable is measured along a continuum at any place beyond the decimal point and can be positive (e.g., height) or negative (e.g., temperature) in value. True/False

True

Random assignment is not possible in a quasi-experiment because the variables being studies cannot be manipulated. True/False

True

When to use a histogram?

When you have interval or ratio data, has no space between categories.

When to use bar graphs?

When you have nominal or ordinal data, includes space between categories

Equidistant Scale

a set of numbers distributed in equal units

correlational method

access relationships between variables, but does not allow for the manipulation of them

frequency distribution

an organized tabulation of the number of individuals located in each category on a scale. Presents two elements: the categories/increments on the measurement scale and the frequency of each score

Why we divide n-1 for sample variability

corrects the bias, since we are using sample and not population to calculate variance.

quasi-experiment

does not include a control group and/or a manipulated independent variable

inferential statistics

drawing conclusions about a population based on sample data from that population

Empirical rule

for a normal distribution, nearly all data will fall within three standard deviations of the mean.

f

frequency

f(x)

frequency of a given score

p

portion of probability

X

score

central tendency

statistics that identify the center of a distribution, most appropriate statistics depend on aspects of distribution

N

total # of scores (or participants)

when to use median

use when data is ordinal or skewed

when to use mode

use when you have nominal data and trying to get a sense of shape

When to use Mean

when the data are continuous and you don't have any extreme scores.