Chapter 0 · Section 5 practice

Modules, NumPy and SciPy

0 of 6 answered

These questions review the examples in the companion slides. Choose an answer, then check the explanation.

Question 1

NumPy is installed, but a freshly restarted kernel reports NameError: np is not defined. What should you run first?

  • import numpy as np
  • %pip install numpy on every restart
  • np = 0

Question 2

In a fresh session, you run from math import sqrt as root. Which call matches that import?

  • math.sqrt(144)
  • sqrt(144)
  • root(144)

Question 3

For values = [2, 5] and array = np.array(values), what does array * 2 contain?

  • [2, 5, 2, 5]
  • [4, 10]
  • The scalar 14

Question 4

For the same five unequal customer counts, why is the result with ddof=1 larger than with ddof=0?

  • The data have changed
  • The mean has doubled
  • The squared deviations are divided by 4 instead of 5

Question 5

A manager wants a time limit that 95% of deliveries meet under a specified normal model. Which operation answers that question?

  • stats.norm.ppf(0.95, loc=28, scale=6)
  • stats.norm.cdf(0.95, loc=28, scale=6)
  • stats.norm.pdf(0.95, loc=28, scale=6)

Question 6

A normal PDF evaluated at 8 minutes gives approximately 0.1995. Which interpretation is correct?

  • Exactly 19.95% of deliveries take 8 minutes
  • This is a density; interval probability is an area under the curve
  • The observed mean must be 8 minutes