Question

friday reading test: unit 1 skills b
article: joly - mascheroni, r. m., senju, a., & shepherd, a. j. (2008). dogs catch human yawns. biology letters, 4(5), 446 - 448
you may not work with others, this assignment will be treated like a test.

1. identify the statistical elements using brief sentences in your own words.

a) what are the cases in this study? what is the sample size?
b) what is the population the researchers intend to generalize to?
c) name one categorical variable in this study and list the different categories of the variable you chose (there are multiple right answers, don’t stress too much)
d) name one quantitative variable in this study and the units in which the variable was measured (there are multiple right answers, don’t stress too much)

1. explanatory vs. response variables - answer the question with complete sentences in your own words.

a) in the main comparison the authors set up, clearly define the explanatory variable and the response variable.

Explanation:

Step1: Identify cases and sample size

The cases are the individual dogs and humans involved in the study. Without access to the full - text article, we assume the sample size is the number of dogs and humans observed. But based on common biological studies, if we assume a typical setup, we might say the sample size is the number of dog - human pairs or individual dogs and humans separately that were part of the data collection. However, without the actual data from the article, we can't give a specific number.

Step2: Determine population to generalize to

The researchers likely intend to generalize to all dogs and all humans. Dogs in general as a species and humans in general are the populations they want to make inferences about regarding the phenomenon of dogs catching human yawns.

Step3: Find categorical variable

One categorical variable could be "presence of yawn" with categories "yawn present" and "yawn absent". When observing dogs and humans, we can classify each observation as whether a yawn occurred or not.

Step4: Find quantitative variable

One quantitative variable could be "number of yawns" with units being "count" or "number". We could count how many times a dog or a human yawned during the observation period.

Step5: Define explanatory and response variables

The explanatory variable in the main comparison could be "whether a human yawned" (a categorical variable with two levels: yes or no). The response variable would then be "whether a dog yawned" (also a categorical variable with two levels: yes or no). The idea is to see if the human's yawn (explanatory variable) influences the dog's yawn (response variable).

Answer:

1.
a) The cases are individual dogs and humans in the study. Sample size is unknown without full - text data.
b) The population is all dogs and all humans.
c) Categorical variable: "presence of yawn", categories: "yawn present", "yawn absent".
d) Quantitative variable: "number of yawns", units: "count".
2.
a) Explanatory variable: Whether a human yawned (yes or no). Response variable: Whether a dog yawned (yes or no).