Unit 9 Statistics Vocabulary

Unit 9 Statistics Vocabulary

You need to copy down all vocab slides into your notes.

Vocab

• 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.

Now that we have selected our sample.....

• Lets look at the three different ways to gather data:

• Survey

• Observational Study

• Experiment

Vocab

• 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.

Multiple Choice

Melanie wants to study the changes in stock prices of companies in the S&P 500, a group of 500 stocks chosen because they represent the U.S. economy. She numbers the companies 1 to 500, obtains a random number from 1 to 20 on a graphing calculator (in this case, 18) and then selects every twentieth company starting at 18 (18, 38, 58, …, 498) to include in her sample.

Which type of sampling method is used?

• Cluster

• Systematic

• Stratified

• Convenience

Multiple Choice

On an assembly line, each employee is assigned a random number using computer software. The same software is used periodically to choose a number of one of the employees to be observed to ensure they are employing best practices.

Which type of sampling method is used?

• Convenience

• Stratified

• Simple Random

• Cluster

Multiple Choice

A test of the effectiveness of a new curriculum could begin by selecting a school district, then choosing 3 schools at random and sampling 100 students from each.

• Cluster

• Stratified

• Simple Random

• Systematic

Multiple Choice

Which type of sample is described by the following situation:

Ms. L’Heureux wants to collect baseline data for writing before her high school begins a new writing program. Each student provides a timed writing sample. Ms. L’Heureux then randomly selects 20 samples from each grade to score with the school-wide writing rubric.

• Cluster Sample

• Stratified Sample

• Systematic Sample

• Simple Random Sample

Correct Answer: Stratified Sample

• Explanation:

• Students are organized in groups (by grade).

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

Multiple Choice

Which type of data collection is used in the following situation:

Researchers wanted to see how long it would take a college-aged cigarette smoker to become short of breath. A study of 200 college age cigarette smokers found that the participants were able to walk on a treadmill set with a steep incline for an average of 0.6 mile before the participants became short of breath.

• Observational Study

• Experiment

• Survey

Correct Answer: Observational Study

• 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.

Vocab

Example:

Correct answer: 107000

• SEM = s/√n

• SEM = 1070000/√100

• SEM = 1070000/10

• SEM = 107000