RiSE 217 - AP STATS

Runners after an ultramarathon commonly develop respiratory infections. We want to know if taking 600 milligrams of vitamin C daily will reduce these infections. Researchers randomly assigned 100 ultramarathon runners to receive either vitamin C or placebo. All subjects were watched for 14 days after the big race to see if infections developed. What are the possible lurking variables?

• Age of the runner
• weight of the runner
• gender of the runner
• all of the above

Tags

CCSS.HSS.IC.B.3

Runners after an ultramarathon commonly develop respiratory infections. We want to know if taking 600 milligrams of vitamin C daily will reduce these infections. Researchers randomly assigned 100 ultramarathon runners to receive either vitamin C or placebo. All subjects were watched for 14 days after the big race to see if infections developed. The type of design used here?

• matched pairs
• randomized block
• completely randomized
• stratified 

Tags

CCSS.HSS.IC.B.3

In order to perform an experiment using 60 members of a gym, I first divide the list of members into men and women because I feel that the results will be different based on gender. I then randomly choose 30 men and 30 women. I assign half of the men to the treatment group and half to the control group. I repeat this procedure with the women. This is an example of a:

• randomized comparative design
• blocking design
• matched pairs design
• double blind simple random sample

Tags

CCSS.HSS.IC.B.3

A market research company wishes to find out whether the population of students at a university prefers Starbucks or Dunkin Donuts. A random sample of students is selected, and each student is asked first to try both but the order they try them is randomly decided with a coin toss (heads: Starbucks, then Dunkin. tails: vice versa). They then indicate which brand they prefer. This is an example of

• a completely randomized experiment
• an observational study
• a stratified sample
• a matched pairs experiment

Tags

CCSS.HSS.IC.B.3

Why do we randomize in an experiment or a survey?

• Because we have to
• It helps reduce the effects of confounding variables
• It eliminates all possible confounding variables
• It makes sampling easier

Tags

CCSS.HSS.IC.B.3

Identify the design  for the experiment

• completely randomized, the factor is pesticide
• randomized block, blocked on tree type, the factor is pesticide
• This experiment is single blind, blocked by pesticide
• The experiment is double blind, the factors are tree type and pesticide

Tags

CCSS.HSS.IC.B.3

The teacher samples her class by selecting all students sitting at group 1 and group 5 in her classroom.  This sampling technique is called?

• SRS
• Stratified
• Systematic
• Cluster

Tags

CCSS.HSS.IC.B.3

At a middle school, the 7th graders will conduct a survey for where to go on a field trip. Which method will result in the least biased decision?

• to randomly ask 8th grade students who went on a field trip last year
• to randomly choose some 7th grade students to select a location
• to ask all 7th grade teachers and administrators for a location
• to ask the student council to choose a location

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

Each student in the school is given a different number.  A student is randomly selected from the first 25. That student and every 25^th student thereafter are in the sample.  This is what type of sampling design?

• SRS
• Systematic
• Multistage
• Stratitfied

Tags

CCSS.HSS.IC.B.3

To check the effect of hot temperatures on the elasticity of two brands of rubber bands, one box of Brand A and one box of Brand B rubber bands are tested. Ten bands from the Brand A box are placed in a warm car in the sun for two hours and ten bands from the Brand B box are kept at room temperature. The amount of stretch before the breakage is measured on each rubber band, and the mean for the hot bands is compared to the mean for the others. Is this a good experimental design?

• No, because the means are not proper statistics for comparison.

• No, because more than two brands should be used.

• No, because more temperatures should be used.

• No, because temperature is confounded with brand.

• Yes

Tags

CCSS.HSS.IC.B.3