Topic II Statistic

Vocabulary  Parameter : In a statistic study, data are collected and used to answer questions about a population characteristic.  Statistic: is calculated using the data. (mean, standard deviation are used to make inference about population parameter).  Bias: is an error that results in a misrepresentation of members of a population.( biased – unbiased )  Random sample: to reduce the possibility of selecting a biased sample and can be taken in which members of population are selected entirely by chance.

The steps in a typical statistic study  Identify the objective of the study.  Choose a sample and collect data.  Organize the data, calculate sample statistics.  Make inferences, and draw conclusions about the populations.

Study Types Definition  Survey: data are collected for responses given by members of a populations regarding their characteristic, behaviors or opinions.  An experiment: the sample is divided into two groups An experimental group that undergoes a change. A control group that does not undergo the change. Examples  To determine whether the students body likes the new cafeteria menu.  The restaurant is considering creating meals with chicken of instead beef. They randomly give half of a group of participants meals with chicken and the other half meals with beef. Then they ask how they like the meals.

Study Types  Observational study: member of a sample are measured or observed without being affected by the study. Ex: Researchers at an electronic company observe a group of teenagers using different laptops and note their reactions.