Stats Exam 1

What is the recommended number of intervals that should be included in a simple frequency distribution?

5 to 20 intervals

population parameter

A characteristic (usually numeric) that describes a population

sample statistic.

A characteristic (usually numeric) that describes a sample

Inferential statistics:

Applying statistics to interpret the meaning of information Inferential statistics are procedures used that allow researchers to infer or generalize observations made with samples to the larger population from which they were selected. Ex: General dislike for sour tasting grape juice

Descriptive statistics

Applying statistics to organize and summarize information Ex: intake of healthy fruit juice

State whether each of the following is continuous or discrete: Delay (in seconds) it takes drivers to make a left-hand turn when a light turns green

Continuous

A researcher measures the relationship between annual income and life satisfaction.

Correlational method

State whether each of the following is continuous or discrete: Type of drug use (none, infrequent, moderate, or frequent)

Discrete

State whether each of the following is continuous or discrete: Number of questions that participants ask during a research study

Discrete

State whether each of the following is continuous or discrete: Season of birth (spring, summer, fall, or winter)

Discrete

A researcher tests whether dosage level of some drug (low, high) causes significant differences in Health.

Experiment

True or false: Qualitative variables can be continuous or discrete.

False. Qualitative variables can only be discrete

A _____________ is a summary display for a distribution of data organized or summarized in terms of how often (or frequently) scores occur.

Frequency distribution

Why is it generally inappropriate to include an open interval in a simple frequency distribution?

Including an open interval can make it difficult to identify if outliers exist in a data set.

Ratio:

Interval scales are measurements that have no true zero and are distributed in equal units. An equidistant scale is a set of numbers distributed in equal units. A true zero is when the value 0 truly indicates nothing on a scale of measurement. Interval scales do not have a true zero. Ratio scales are measurements that have a true zero and are distributed in equal units.

A researcher measures four variables: age (in days), speed (in seconds), height (in inches), and movie ratings (from 1 to 4 stars). Which of these variables is not an example of a variable measured on a ratio scale?

Movie ratings (from 1 to 4 stars)

In 2010, Fortune magazine ranked Apple as the most admired company in the world. This ranking is on a(n) ____________scale of measurement.

Ordinal

Ordinal

Ordinal scales are measurements that convey order or rank alone. Ex: top colleges in the US for HR

A researcher is interested in the effects of stuttering on social behavior with children. He records the number of peers a child speaks to during a typical school day. In this example, would the data be quantitative or qualitative?

Quantitative.

A researcher tests whether citizens of differing political affiliations (Republican, Democrat) will show differences in attitudes toward morality.

Quasi-experiment.

____________ are rules for how the properties of numbers can change with different uses.

Scale of measurement.

1. ____________ is the study of phenomena through strict observation, evaluation, interpretation, and theoretical explanation.

Science

Interval

This type of scale is a numeric response scale used to indicate a participant's level of agreement or opinion with some statement. DOES NOT HAVE TRUE ZERO Ex: if you are asked to rate your satisfaction with a spouse or job on a 7-point scale from 1 (completely unsatisfied) to 7 (completely satisfied), then you are using an interval scale

Each of the following is a rule for the simple frequency distribution except: A. Each interval is equidistant. B. The same score cannot occur in more than one interval. C. Each interval is defined (it has a lower and an upper boundary). D. The interval width is equal to the number of intervals in a frequency distribution.

The interval width is equal to the number of intervals in a frequency distribution.

True or false: A ratio scale variable can be continuous or discrete.

True

True or false: A researcher observes that a single parent works 42.25 hours per week. The degree of accuracy of 42.25 is to the hundredths place (.01).

True;

What are two characteristics of rating scales that allow researchers to use these values on an interval scale of measurement? A. Values on an interval scale have a true zero but are not equidistant. B. Values on an interval scale have differences and a true zero. C. Values on an interval scale are equidistant and have a true zero. D. Values on an interval scale are assumed to be equidistant but do not have a true

Values on an interval scale are assumed to be equidistant but do not have a true

quantitative variable

Varies by amount. This variable is measured numerically and is often collected by measuring or counting.

Quasi-experimental

a preexisting variable that is often a characteristic inherent to an individual, which differentiates the groups or conditions being compared in a research study. Because the levels of the variable are preexisting, it is not possible to randomly assign participants to groups.

A sample

a set of individuals, items, or data selected from a population of interest.

simple frequency distribution

a summary display for (1) the frequency of each individual score or category (ungrouped data) in a distribution or (2) the frequency of scores falling within defined groups or intervals (grouped data) in a distribution.

frequency distribution

a summary display for a distribution of data organized or summarized in terms of how often a category, score, or range of scores occurs.

pen interval

an interval with no defined upper or lower boundary.

Grouped data

are a set of scores distributed into intervals, where the frequency of each score can fall into any given interval.

Outliers

are extreme scores that fall substantially above or below most of the scores in a particular data set.

Interval boundaries

are the upper and lower limits for each interval in a grouped frequency distribution.

Correlational-

can determine whether a relationship exists between variables, but it lacks the controls needed to demonstrate cause and effect.

interval

discrete range of values within which the frequency of a subset of scores is contained.

discrete variable

is measured in whole units or categories that are not distributed along a continuum.

Real range

is one more than the difference between the largest and smallest values in a data set.

lower boundary

is the smallest value in each interval of a frequency distribution;

continuous variable

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

Nominal statistics

measurements in which a number is assigned to represent something or someone. Coding is the procedure of converting a nominal or categorical variable to a numeric value. Ex: zip codes, license plates, credit cards, telephone numbers

upper boundary

the largest value in each interval of a frequency distribution.

qualitative variable

varies by class. This variable is often represented as a label and describes nonnumeric aspects of phenomena.

Frequency

the number of times or how often a category, score, or range of scores occurs.

Population

the set of all individuals, items, or data of interest. This is the group about which scientists will generalize.

True or false: An experiment is the only method that can demonstrate cause-and-effect relationships

true

interval

width or class width is the range of values contained in each interval of a grouped frequency distribution.