Unit 9 Statistics Vocabulary

Sample: portion of the population you are gathering data on/for.

Simple Random Sample: randomly select number needed for sample from population (ex: picking names out of a hat)

Cluster Sample: separate population into naturally occurring groups (ex: geographic location), then randomly select groups needed for sample. Not all groups will be chosen.

Systematic Sample: Using an ordered list of the population (by name, arrival time, etc.) select every nth member, randomly select the starting point.

Stratified Sample: group the population based on relevant characteristic(s). Randomly select the same number of members from each group so each group is represented in the sample.

Lets look at the three different ways to gather data:

Survey

Observational Study

Experiment

Sample Survey: a study of particular qualities or attributes of items or people of interest to the researcher (ex: any survey you have taken for school).

Observational Study: a study in which all data are recorded in a way that does not change the subject that is being measured or studied. Also used when an experiment may be unethical, like to see how smoking affects the body. You cannot force people to smoke, so you conduct an observational study on people who already smoke.

Experiment: In an experiment participants are intentionally subjected to some process, substance, or action and the results are observed and recorded. Many times an experiment has a control group who are not being subjected to the treatment, process, or action being studied in the experiment.

Explanation:

Students are organized in groups (by grade).

The teacher chose 20 students from each grade meaning every group is represented in the same.

Explanation:

In order to see the effects of smoking cigarettes on how long it takes a college-aged student to become short of breath they cannot conduct an experiment, that would be unethical. They can only have people who are currently smokers volunteer for the study to walk on the treadmill and observe when they become short of breath.

SEM = s/√n

SEM = 1070000/√100

SEM = 1070000/10

SEM = 107000