Exam 1: Data Collection

A medical journal published the results of an experiment on insomnia. The experiment investigated the effectsof a controversial new therapy for insomnia. Researchers measured the insomnia levels of 90 adult women whosuffer moderate conditions of the disorder. After the therapy, the researchers again measured the womenʹsinsomnia levels. The differences between the the pre- and post-therapy insomnia levels were reported.Identify the experimental units.

Determine whether the quantitative variable is discrete or continuous. -the number of goals scored in a hockey game

An experiment in which neither the experimental unit nor the researcher in contact with the experimental unitknows which treatment the experimental unit is receiving is called a ________________ .

Identify the type of sampling used. -A market researcher randomly selects 100 homeowners under 60 years of age and 200 homeowners over 60years of age. What sampling technique was used?

Identify the type of sampling used. -Based on 9000 responses from 26,500 questionnaires sent to all its members, a major medical associationestimated that the annual salary of its members was $99,000 per year. What sampling technique was used?

Determine what type of observational study is described. Explain. -Researchers wanted to determine whether there was an association between high blood pressure and thesuppression of emotions. The researchers looked at 1800 adults enrolled in a Health Initiative ObservationalStudy. Each person was interviewed and asked about their response to emotions. In particular they were askedwhether their tendency was to express or to hold in anger and other emotions. The degree of suppression ofemotions was rated on a scale of 1 to 10. Each personʹs blood pressure was also measured. The researchersanalyzed the results to determine whether there was an association between high blood pressure and thesuppression of emotions.

Classify the variable as qualitative or quantitative. -the colors of book covers on a bookshelf

Determine whether the study depicts an observational study or an experiment -A scientist was studying the effects of a new fertilizer on crop yield. She randomly assigned half of the plots ona farm to group one and the remaining plots to group two. On the plots in group one, the new fertilizer wasused for a year. On the plots in group two, the old fertilizer was used. At the end of the year the average cropyield for the plots in group one was compared with the average crop yield for the plots in group two.

Determine whether the quantitative variable is discrete or continuous. -the weight of a player on the wrestling team

Determine the level of measurement of the variable. -the day of the month

Classify the variable as qualitative or quantitative. -the temperatures of cups of coffee served at a restaurant

Determine whether the quantitative variable is discrete or continuous. -The peak shopping time at a pet store is between 8-11:00 am on Saturday mornings. Management at the petstore randomly selected 65 customers last Saturday morning and decided to observe their shopping habits.They recorded the number of items that a sample of the customers purchased as well as the total time thecustomers spent in the store. Identify the types of variables recorded by the pet store.

A salesman boasts to a farmer that his new fertilizer will increase the yield of the farmerʹs crops by 15%. Thefarmer wishes to test the effects of the new fertilizer on her corn yield. She has four equal sized plots of land-one with sandy soil, one with rocky soil, one with clay-rich soil, and one with average soil. She divides eachof the four plots into three equal sized portions and randomly labels them A, B and C. The four A portions aretreated with her old fertilizer. The four B portions are treated with the new fertilizer. The four C portionsreceive no fertilizer. At harvest time, the corn yield is recorded for each section of land. What is the claim sheis testing?

Determine whether the quantitative variable is discrete or continuous. -the speed of a car on a Boston tollway during rush hour traffic

Determine the level of measurement of the variable. -the medal received (gold, silver, bronze) by an Olympic gymnast

Determine whether the underlined value is a parameter or a statistic. -28.2% of the mayors of cities in a certain state are from minority groups.

Classify the following random variable: telephone area codes

The policy committee at State University has 6 members: LaToyna, Ming, Jose, John, Prof. Rise, andDr. Hernandez. A subcommittee of two members must be formed to investigate the visitation policy in thedormitories. List all possible simple random samples of size 2.

Determine whether the study depicts an observational study or an experiment -A researcher obtained a random sample of 100 smokers and a random sample of 100 nonsmokers. Afterinterviewing all 200 participants in the study, the researcher compared the rate of depression among thesmokers with the rate of depression among nonsmokers.

Determine whether the underlined value is a parameter or a statistic. -51.5% of the residents of Idlington Garden City are female.