An advertising firm conducts 3 different campaigns, each in 14 ...

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An advertising firm conducts 3 different campaigns, each in 14 different cities, to promote a certain product, and tracks the product sales attributable to each campaign in each city. Determine whether the study is observational or designed.
 
  A) observational B) designed

Question 2

An educator wanted to look at the study habits of university students.
 
  As part of the research, data was collected for three variables - the amount of time (in hours per week) spent studying, the amount of time (in hours per week) spent playing video games and the GPA - for a sample of 20 male university students. As part of the research, a 95 confidence interval for the average GPA of all male university students was calculated to be: (2.95, 3.10). Which of the following statements is true?
  A) In construction of the confidence interval, a t-value with 19 degrees of freedom was used.
  B) In construction of the confidence interval, a t-value with 20 degrees of freedom was used.
  C) In construction of the confidence interval, a z-value with 20 degrees of freedom was used.
  D) In construction of the confidence interval, a z-value was used.

[voltaire123]

Answer to Question 1

B

Answer to Question 2

A

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Gracias!

[Sarahjh]

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