STATS Test 1

Cluster sampling

a sampling technique in which clusters of participants that represent the population are used

z-score sample

x - overbar x / s

z-score population

x - weird u / weird o

Types of sampling

-cluster -simple random -stratified -systematic

Lower quartile

25%

Upper quartile

75%

Population vs. Sample

A population includes all of the elements from a set of data. A sample consists of one or more observations from the population.

What is a representative​ sample? What is its​ value?

A representative sample is a sample that exhibits characteristics typical of those possessed by the population of interest. It is valuable because these characteristics allow inferential statistics to be applied.

Chebychev rule

Not mound and symmetric 3/4 within 2 8/9 within 3

A research company performed a study of Machiavellian traits in accountants. Machiavellian describes negative character traits that include​ manipulation, cunning,​ duplicity, deception, and bad faith. A questionnaire was administered to a random sample of 700 acccounting alumni of a large​ university; however, due to nonresponse and incomplete​ answers, only 175 questionnaires could be analyzed. Several variables were​ measured, including​ age, gender, level of​ education, income, job satisfaction​ score, and Machiavellian​ ("Mach") rating score. The research findings suggest that Machiavellian behavior is not required to achieve success in the accounting profession. a. Identify the population of interest to the researchers. b. Identify the sample. c. Use the information in the study to make an inference about the relevant population.

A. All accounting alumni of the large university B. The sample is the 175 accounting alumni who returned the questionnaire. C. Machiavellian behavior is not required to achieve success in the accounting profession.

What is​ statistics?

It is the science that deals with​ collection, classification,​ analysis, and interpretation of information or data.

Lower inner fence

Lower hinge-1.5(IQR)

Empirical rule

Mound and symmetric 68% within 1 95% within 2 99.7% within 3

Explain the difference between descriptive and inferential statistics.

Descriptive statistics describes sets of data. Inferential statistics draws conclusions about the sets of data based on sampling

Systematic sampling

Every nth item in the target population is selected

Identify the type of sampling used​ (simple random,​ systematic, convenience,​ stratified, or cluster​ sampling) in the situation described below. A woman is selected by a marketing company to participate in a paid focus group. The company says that the woman was selected because every 1000th person in the phone number listings was being selected.

Systematic sampling

frequency vs relative frequency

The class frequency is the number of observations in the data set falling into a particular class. A frequency histogram is a histogram showing the class frequency of the observations. The class relative frequency is the class frequency divided by the total number of observations in the data set. A relative frequency histogram is a histogram showing the relative frequency of each class. The histogram displayed is a frequency histogram because the histogram displays the class frequency of the data.

Interquartile range

The difference between the upper and lower quartiles.

Determine whether the study depicts an observational study or an experiment. A study is conducted to determine if there is a relationship between heart arrhythmias and caffeine consumption. A sample of 100 people with a heart arrhythmia are asked about their caffeine consumption.

The study is an observational study because the study examines individuals in a sample, but does not try to influence the response variable.

Name and describe the three most important measures of central tendency.

The​ mean, median, and mode are the most important measures of central tendency. The mean of a data set is its arithmetic average. The median of a data set is the middle value in its ordered list. The mode of a data set is its most frequently occurring value.

Upper Inner Fence

Upper hinge + 1.5 (IQR)

A company surveyed a random sample of 4,500 employees in the region. One question they asked​ was, "If your employer provides you with mentoring opportunities are you likely to remain in your job for the next five​ years?" They found that 700 members of the sample said yes. a. Identify the population of interest to the company. b. Based on the question posed by the company what is the variable of​ interest? c. Is the variable quantitative or​ qualitative? d. Describe the sample.

a. All employees in the region b. If they answered yes to the survey question c. The variable is a qualitative variable. Its values cannot be expressed on a naturally occurring numerical scale. d. The 4,500 employees surveyed

How many measurements on a bar graph

add number displayed by each bar

To determine customer opinion of their food quality food quality​, General Foods randomly selects 80 city blocks during a certain week and surveys all homes within the city blocks. What type of sampling is​ used?

cluster sampling

A sample data set has a mean of 74 and a standard deviation of 10. Determine whether each of the following sample measurements are outliers.

do z score x - overbar x / s x = sample measurement x overbar = mean s = standard deviation

Simple random sampling

every member of the population has an equal probability of being selected for the sample

Class intervals on bar graph

number of bars

A​ _________________ is a numerical measurement describing some characteristic of a population.

parameter

Stratified random sampling

separation of the target population into different groups, called strata, and the selection of samples from each stratum

A​ _________________ is a numerical measurement describing some characteristic of a sample.

statistic