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Which of the following statements is NOT true?
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?
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
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.
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?
Which of the following could be the lurking variable here?
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.
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
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.
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