ISCAM

Name*

First NameLast Name
Name 2

First NameLast Name
E-mail (This person will submit the pdf)*
example@example.com
What section are you in?

Section 1 (9-10am)Section 2(10-11am)
Goals: In this lab, you will
- Practice applying and interpreting two-sample t-procedures.
Background

Researchers conducted a study in which they invited members of the Department of Food Science and Nutritional Science (faculty, graduate students, and staff) at a large midwestern university to an ice cream social (Mindless Eating: Why we eat more than we think, Wansink et al., 2006). The participants were randomly given either a 17- or a 34-ounce bowl. Participants individually helped themselves to the available ice cream in the cafeteria line, unaware that other participants had been given different-sized bowls. The suspicion was that even nutrition experts would tend to take more ice cream when given a larger bowl.

Research question: Do nutrition experts tend to take more ice cream when given a larger bowl than when given a smaller bowl?

Study Design

Sample results for the actual volumes of ice cream taken (in ounces) are summarized in the following table:

	Sample size	Sample mean	Sample SD
17-ounce bowl	20	4.38	2.05
34-ounce bowl	17	5.81	2.26

(a) Summarize the study design
What is the observational unit? blank
What is the explanatory variable? blank
What is the response variable? blank
What is the sample sizes for each group? blank
(b) Is this an experimental study or an observational study? Briefly justify.
Suppose I define the parameter μ17oz - μ34oz. Which of the following would be the best definition of this parameter?

The difference in the long run mean serving size of ice cream when using a 17oz bowl and using a 34oz bowlThe difference in the population mean serving size of ice cream between those using 17oz bowls and those using 34oz bowlsThe difference in the sample mean serving size of ice cream between those using the 17oz bowl and those using the 34oz bowlThe difference in the sample mean serving size of ice cream between those who used the 17oz bowl and those who used the 34oz bowlOther
(c) Write out the null and alternative hypotheses, in words, for this research study in terms of the above parameter.
Symbols you might be able to copy and paste?

μ σ s n ≤ ≥ ≠ x̄ p̂ 𝑝̂

Statistical Inference
(d) Would it be possible for you to carry out a randomization test using simulation with the information presented here? Explain.
(e) Use technology (R or JMP or the Theory-Based Inference applet) to carry out a two-sample t-test to determine whether individuals given a 34-oz bowl have a tendency to serve themselves more ice cream than individuals given a 17-oz bowl. Be sure to report your test statistic and p-value. Also determine a 95% t-confidence interval for the difference in the long-run average serving size.
Include a screen capture of the output.

Cancelof
Also report the following:
Test statistic: blanks
p-value: blank
Confidence interval: blank
What can you say about the validity (technical conditions) for these two-sample t-procedures?

Conclusions
(f) Write a paragraph summarizing your conclusion as if to a nutrition expert. Your conclusion should address (and justify) the statistical significance of the data, your estimate the size of the parameter, whether you are willing to draw a cause-and-effect conclusion, and the population to which you are willing to generalize the results.
For this lab, after you submit Jotform will send you an email with a pdf attachment. Upload this pdf file into Canvas.

If you worked with a partner on this lab, both of you need to join a Lab 8 group before submitting.
Should be Empty:

Background

Study Design

Statistical Inference

Conclusions