Homework 2

1. The provided code splits the body temperature data into two groups by sex. Use this data to do the following.

   1. Compute a 90% confidence interval for the mean female body temperature and interpret the interval in context in the style introduced in class.
   2. Compute a 90% confidence interval for the mean male body temperature and interpret the interval in context in the style introduced in class.
   3. Based on your intervals, is it plausible that there is no difference in mean temperature by sex? Why or why not?

Solution

load('data/temps2.RData')

# split observations into two groups by sex
temps.split <- split(temps$body.temp, temps$sex)

# store male and female temperatures
temps.m <- temps.split$male
temps.f <- temps.split$female

# part a: confidence interval for mean body temps for female

# part b: confidence interval for mean body temps for male

1. [your answer here]
2. [your answer here]
3. [your answer here]

2. The armspans dataset contains the 32 armspan measurements from last class.

   1. Construct a histogram of the armspans and describe its shape.
   2. Would an armspan of 201cm be unusual? Explain.
   3. Find your armspan (the command view(armspans) will open the data table in a viewer window). Which quartile of the class are you in with respect to armspan?
   4. Pretend that our class is a representative sample of some broader population with respect to armspan. Compute and interpret a 95% confidence interval for the mean armspan.

Solution

# load armspan data

# part a: construct a histogram

# part b: would 201cm be unusual? (hint: check deviation relative to sd)

# part c: find your armspan and compute percentile

# part d: confidence interval for mean armspan

1. [your answer here]
2. [your answer here]
3. [your answer here]
4. [your answer here]