Workshop Statistics
Lab 1

Prelab 1: Background 2: Files 3: Numerical Summary 4: Graphical Summary 5: Discussion 6: Thought Questions 7: Key Question 8: Simulation 9: Coin Tossing 10: Analysis 11: Terminology Detour 12: Conclusions 13: Plausible values 14: Lab Report

Workshop Statistics Lab 1 PreLab

Background: A recent investigation reported in the November 2007 issue of Nature (Hamlin, Wynn, and Bloom) aimed at assessing whether infants take into account an individual's actions towards others in evaluating that individual as appealing or aversive, perhaps laying for the foundation for social interaction.  In one component of the study, 10-month-old infants were shown a "climber" character (a piece of wood with "google" eyes glued onto it) that could not make it up a hill in two tries.  Then they were shown two scenarios for the climber's next try, one where the climber was pushed to the top of the hill by another character ("helper") and one where the climber was pushed back down the hill by another character ("hinderer"). Each infant was alternately shown these two scenarios several times. Then the child was presented with both pieces of wood (the helper and the hinderer) and asked to pick one to play with. Press the arrow under the video to play the following two videos (there is a bit of sound) to see what was shown to the infants for the helper toy and then the hinderer toy. If you cannot see the two videos below, you can try this here for information about using QuickTime on your computer.

helper toy	hinderer toy
Notice how happy the object is when it gets to the top!

If your computer can run QuickTime videos from the web, you may also want to view the third and fourth videos on this page to see how the objects were presented to the infants.

Pre-lab Instructions: Answer the following questions the best you can with your current knowledge. 

(a) Based on the above description of the study, identify the following terms in the context of this study.

observational units:
variable:
research question:

In the Methdology section of the paper, the authors state: "Subjects were healthy full-term infants recruited from greater New Haven area… Ten-month-olds ranged from 9 months and 12 days to 10 months 16 days…..” Based on this, we will assume the population is all healthy 10-month-old infants in New England.

(b) Assuming this to be a reasonable population, how can we define the parameter (a number summarizing the variable in the population of interest)?

The Methodology section also states that for the 10-month-olds, the climber was a yellow triangle; helper and hinderer were a red square and a blue circle (counterbalanced). Also counterbalanced were which event (helping or hindering) they observed first and the positions of helper and hinderer when presented to the infants.

(c) Why are these important considerations? How do they impact the potential conclusions we can draw from this study?

 

(d) How many of the 16 infants in the study would need to choose the helper toy rather than the hinderer toy to convince you that the infants really are showing a preference for the helper toy and aren't just choosing blindly between them? Or would no outcome be convincing to you? Explain your reasoning.

(e) Suppose your instructor tosses a coin 16 times and tells you how many times she flipped heads. How many heads would she need to report to convince you that she had some special ability to toss heads more often than tails? Explain your reasoning.

(f) Explain how the questions about a coin's result might help to assess the evidence provided by the selections of the 16 infants in this study.