Which of the following statements are correct in regards to sampling in scientific investigations?

1. The sample should be small in order to produce accurate and valid results.
2. The sample should reflect the characteristics of the larger targeted population.
3. The sample should be selected at random so that every individual in the larger target population has the same likelihood of being chosen.

A. I and II are correct
Incorrect. II is correct. The sample should reflect the characteristics of the larger targeted population; sample sizes should be large.

B. I and III are correct.
Incorrect. III is correct. The sample should be selected at random; sample sizes should be large.

C. III is correct
Incorrect. More than one of the statements are correct. Samples should be selected at random, so III is one of the correct statements. What other statement is also correct?

D. II and III are correct.
Correct!

A. Vague statements
Incorrect. Vague statements make the explanation unreliable.

B. Repeatable data
Correct! If the investigation is repeated and the data is the same then the scientific explanation can be considered reliable.

C. Notes taken after the investigation
Incorrect. Detailed notes should be taken during an investigation.

D. Several likely explanations
Incorrect. Several likely explanations make the explanation unreliable.

A. The manufacturer of the product
Incorrect. The manufacturer is trying to sell its product and will tell you the good points, not the bad.

B. A government study of the product
Correct! The government is most likely to be unbiased since they have no commercial interest in the product.

C. A television advertisement
Incorrect. Advertisements are most likely trying to sell the product or a competitor’s product. The information given is likely to be mostly positive not negative.

D. One of the manufacturers competitors
Incorrect. The competitor will emphasize the negative aspects of the product in order to sell their own items.