Gestation classroom exercise

16 Jun 2015

#Objective We are learning about univariate descriptive plots and statistics: the histogram, box-and-whisker plot, mean, pecentiles, standard deviation. Additionally, we emphasize that plotting is the first step to understanding your data. The distinction between descriptive/inferential statistics is something we’ve talked about - the last question is supposed to inspire some critical thinking.

#Setup I sampled 80 babies from the “Birth Weight II” data set at Deborah Nolan and Terry Speed’s Stat Labs website. For each baby, I wrote its gestation length (in days) on a cheap white poker chip. The chips were placed in one communal basket at the head of the class - each team sent a sampler and a recorder up to draw their sample. I assigned different sample sizes to each group (11, 15, or 19, to make quartiles easy).


Sample your data

Your group has been assigned a sample size. From the central urn, draw your sample with replacement:

  1. Grab one chip from the urn
  2. Note the gestation length written on the chip and add it to your list.
  3. Return the chip the the urn and repeat.

Calculate summary statistics

Calculate the min, max, mean, median, first and third quartile, IQR, and standard deviation.

Plot the data

Based on your sample, make a box-and-whisker plot of gestation period. Annotate it with the statistics you calculated in the previous step. How many of the samples were within one standard deviation of the mean?


Answer each of the following in about two sentences:

  • Describe one way in that your work is descriptive statistics.
  • Argue for why this is actually inferential statistics, and describe the population that your sample represents.

Markdown is allowed. Email addresses will not be published.