click below

click below

Normal Size Small Size show me how

# MMB Stats CH 1

### Ch 1 Larson

Question | Answer |
---|---|

Data | consist of information coming from observations, counts, measurements, or responses. |

Statistics | the science of collecting, organizing, analyzing, and interpreting data in order to make decisions. |

Population | the collection of all outcomes, responses, measurements, or counts that are of interest. |

Sample | a subset of a population. |

Parameter | a numerical description of a population characteristic. |

Statistic | a numerical description of a sample characteristic. |

Descriptive statistics | the branch of statistics that involves the organization, summarization, and display of data. |

Inferential statistics | the branch of statistics that involves using a sample to draw conclusions about a population. A basic tool in the study of inferential statistics is probability. |

Qualitative data | consist of attributes, labels, or nonnumerical entries. |

Quantitative data | consist of numerical measurements or counts. |

Nominal level of measurement | qualitative only. Data at this level are categorized using names, labels, or qualities. No mathematical computations can be made at this level. |

Ordinal level of measurement | qualitative or quantitative data. Data at this level can be arranged in order, or ranked, but differences between data entries are not meaningful. |

Interval level of measurement | data that can be ordered, and you can calculate meaningful differences data entries. At this level, a zero entry simply represents a position on a scale; the entry is not an inherent zero. |

Ratio level of measurement | data that are similar to data at the interval level, with the added property that a zero entry is an inherent zero. A ratio of two data values can be formed so that one data value can be meaningfully expressed as a multiple of another. |

Observational study | a method of gathering data in which a researcher observes and measures the characteristics of interest of part of a population but does not change existing conditions. |

Experiment | a method of gathering data in which a researcher applies a treatment to part of the population and then observes and measures the responses of interest of part of a population. |

Control group | the part of the population to which no treatment is applied in an experiment. |

Experimental units | the subjects involved in an experiment. |

Placebo | a harmless, unmediated treatment given to subjects in an experiment; it is made to look like the real treatment. |

Simulation | a method of gathering data that uses a mathematical or physical model to reproduce the conditions of a impractical, expensive, or dangerous situation or process. |

Survey | a method of gathering data which is an investigation carried out by asking people questions by interview, mail, or telephone. |

Confounding variable | occurs when an experimenter cannot tell the difference between the effects of different factors on a variable. |

Placebo effect | occurs when a subject reacts favorably to a placebo when in fact he or she has been given no medicate treatment at all. |

Blinding | a technique where the subject does not know whether he or she is receiving a treatment or placebo. |

Double-blind experiment | neither the subject nor the experimenter knows if the subject is receiving a treatment or a placebo. The experimenter is informed after all the data have been collected. |

Randomization | a process of randomly assigning subjects to different treatment groups in an effort to obtain unbiased results. |

Completely randomized design | subjects are assigned to different treatment groups through random selection. |

Blocks | groups of subjects with similar characteristics. |

Randomized Block design | subjects are divided into blocks with similar characteristics, and then within each block they are randomly assigned to treatment or control grops. |

Matched pairs design | subjects are paired up according to a similarity. One subject in the pair receives one treatment while the other subject receives a different treatment. |

Replication | repetition of an experiment using a large group of subjects to improve the validity of experimental results. |

Census | a count or measure of the entire population. |

Sampling | a count or measure of a representative part of the population. |

Sampling error | the difference between the results of sampling and those of the population. |

Random sample | every member of the population has a equal chance of being selected. |

Simple random sample | every possible sample of the same size has the same chance of being selected. |

Stratified sample | a sampling technique used when it is important to have members from each segment or the population; the population is divided into subsets that share a similar characteristic and some members of each group are randomly selected for the study. |

Cluster sample | a sampling technique used when the population falls into naturally occurring subgroups, each sharing similar characteristics; the populations is divided into groups and then all members of one or more groups are selected for the study |

Systematic sample | a sampling technique in which each member the population is assigned a number, a starting point is randomly selected, and sample members are chosen at regular intervals from the starting number. |

Convenience sample | a sampling technique that often leads to biased studies because it consists or only available members of the population. This method is not recommended. |