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Worksheet: Types of Studies

Q1:

Which of the following statements is NOT true?

  • AIn an observational study, the variables are observed and recorded.
  • BIn an experiment, the variables are controlled.
  • CWell-designed experiments allow cause and effect to be established.
  • DObservational studies most often allow cause and effect to be established.
  • EIn an experiment, a treatment is performed on subjects to measure its effect.

Q2:

A large garden furniture seller wants to compare the resistance of two of their product lines in real use conditions. They decide to produce a random sample from their client database and ask them about the conditions of their garden furniture while recording the time of their purchase. Which of the following is probably NOT a confounding variable?

  • Ahow clients store their garden furniture in winter
  • Bnumber of people in the household
  • Cage of the people in the household
  • Dmonth in which the furniture was purchased
  • Eclimate in which the furniture is kept

Q3:

Is the following a survey, an observational study, or an experiment?

A company has developed nontoxic oil paints. To investigate whether this new, environment-friendly product has attracted new clients, client and sale data were analyzed.

  • Asurvey
  • Bexperiment
  • Cobservational study

Q4:

Is the following a survey, an observational study, or an experiment?

A company has developed nontoxic oil paints. To investigate whether the paint adhesion depends on the roughness of the surface to be painted, they produced different samples of different roughness levels, painted the surface, and evaluated the paint adhesion with a paint scrape adhesion test.

  • Asurvey
  • Bobservational study
  • Cexperiment

Q5:

A negative correlation has been observed between the number of pirates in the world and the global average earth temperature; that is, the fewer pirates there are, the colder the earth's temperature.

Do you believe one can conclude that the decline in the number of pirates causes global warming?

  • Ano
  • Byes

Which of the following could be the lurking variable here?

  • Atime
  • Bdeforestation
  • Cclimate
  • Dregion of the world
  • Eglacier melt

Q6:

Is the following a survey, an observational study, or an experiment?

To investigate whether the curing effect of a given drug depends on gender, two randomly selected groups of boys and girls were given this drug while two other randomly selected groups of boys and girls were given a placebo.

  • Aobservational study
  • Bsurvey
  • Cexperiment

Q7:

Is the following a survey, an observational study, or an experiment?

To investigate whether the ability to memorize text depends on gender, two randomly selected groups of boys and girls were given the same text to memorize. After 15 min, they were asked to reproduce the text in writing and their productions were evaluated.

  • A experiment
  • B survey
  • C observational study

Q8:

Identify whether the following study is a survey, an observational study, or an experiment.

Specially designed multifocal contact lenses have been shown to reduce the progression of nearsightedness in children. To investigate whether the obtained results depend on the age at which nearsighted children start wearing the contact lenses, a group of opticians analyzed their patient databank in terms of the age children started wearing the contact lenses and the progression of their nearsightedness after five years compared with nearsighted children who wore only glasses.

  • A Survey
  • B Experiment
  • C Observational study