07 Jan Choose a random sample

MATH399 Applied Managerial Statistics

Week 1 Assignment Statistical Study Design

QuestionA farmer divided his land into 2 groups of sections randomly. There is no difference in the quality of the soil between the 2 groups of land. He used Type A seeds in the first group and Type B seeds in the second group. After 3 months, the heights of the crops are measured across the two groups of land sections. Is the study observational or experimental? If it is an experiment, what is the controlled factor?

The study is an observational study.

The study is an experiment. The controlled factor is the seed type.

The study is an experiment. The controlled factor is the land.

The study is an experiment. The controlled factor is the growth of the crops.

QuestionIn a study to add a new feature to a software program, the programmer introduced two categories, men and women, in the survey she conducted. Is the study observational or experimental? If it is an experiment, what is the controlled factor?

The study is an experiment. The controlled factor is the feature to be added in the software.

The study is an experiment. The controlled factor is the category, men or women.

The study is an observational study.

The study is an experiment. The controlled factor is the survey.

QuestionA study was performed with a random sample of 5 people from a certain city. What population would be appropriate for generalizing conclusions from the study, assuming the data collection methods used did not introduce biases?

The conclusions should be restricted to only the city that was sampled.

The conclusions are generalizable to all people on Earth.

The conclusions are generalizable to all people in the country.

The conclusions apply only to the sample.

The conclusions apply to people in any city.

QuestionA researcher is interested in the effects of watching videos just before bed on the quality of sleep. Which of the following claims would be appropriate for this situation? Select only one answer choice.

Watching videos just before bed reduces quality of sleep.

More than 60% of people watch videos just before going to bed.

Watching 1 hour of video just before going to bed reduces the number of minutes of REM sleep by more than 10%.

Watching 1 hour of video just before going to bed reduces the quality of sleep.

QuestionA researcher wants to evaluate the effect of using Facebook on happiness. Would an experimental or observational study design be more appropriate?

An experimental study should be used with the use of Facebook as the controlled factor.

An experimental study should be used with happiness as the controlled factor.

An observational study should be used because it is not possible to control the use of Facebook.

An observational study should be used because it is not possible to control happiness.

QuestionAn energy drink manufacturer wants to find out the effect of different amounts of their product on the maximum anaerobic power level for rowers. Would an experimental or observational study design be more appropriate?

An experimental study should be used with the maximum anaerobic power as the controlled factor.

An experimental study should be used with the amount of the drink consumed as the controlled factor.

An observational study should be used because the amount of the drink consumed cannot be controlled.

An observational study should be used because the maximum anaerobic power cannot be directly controlled.

QuestionA researcher is interested in the effects of watching videos just before bed on the quality of sleep. He has decided to test the claim “Watching 1 hour of video just before going to bed reduces the number of minutes of REM sleep by more than 10%. ” Which of the following data collection processes would be appropriate? Select only one answer choice.

Choose a random sample of people and ask them how many hours of video they watched last night and how much REM sleep they had.

Choose a random sample of people. Randomly select half of them and have them watch one hour of video just before going to bed, and then monitor their sleep. Have the other half not watch any video and monitor their sleep.

Choose a random sample of people. On multiple randomly selected nights, randomly assign each person to either watch one hour of video or not watch video and monitor their sleep.

Choose a random sample of people. On multiple randomly selected nights, measure the amount of video they watch and monitor their sleep.

QuestionA study was performed with a random sample of 513 bolts produced at one factory. What population would be appropriate for generalizing conclusions from the study, assuming the data collection methods used did not introduce biases?

The conclusions would apply to all bolts produced by that factory.

The conclusions would apply to all bolts produced by any factory run by the same company.

The conclusions would apply to all bolts of the same type produced by any manufacturer.

The conclusions apply only to the bolts in the sample.