the power of statistics coursera weekly challenge 3 answers

Test your knowledge: Introduction to sampling

1. A data professional is conducting an election poll. As a first step in the sampling process, they identify the target population. What is the second step in the sampling process?

  • Select the sampling frame
  • Choose the sampling method
  • Determine the sample size
  • Collect the sample data

2. Fill in the blank: In a _____ sample, every member of a population is selected randomly and has an equal chance of being chosen.

  • cluster
  • snowball
  • simple random
  • voluntary response

3. Non-probability sampling includes which of the following sampling methods? Select all that apply.

  • Systematic random sampling
  • Stratified random sampling
  • Convenience sampling
  • Purposive sampling

Test your knowledge: Sampling distributions

4. A data professional is analyzing data about a population of aspen trees. They take repeated random samples of 10 trees from the population and compute the mean height for each sample. Which of the following statements best describes the sampling distribution of the mean?

  • The sampling distribution of the mean is the sum of all the sample means.
  • The sampling distribution of the mean is the maximum value of all the sample means.
  • The probability distribution of all the sample means
  • The average value of all the sample means.

5. The central limit theorem implies which of the following statements? Select all that apply.

  • If you take a large enough sample of the population, the sample mean will be roughly equal to the population mean.
  • If you take a small enough sample of the population, the sample mean will be roughly equal to the population mean.
  • The sampling distribution of the mean approaches a normal distribution as the sample size decreases.
  • The sampling distribution of the mean approaches a normal distribution as the sample size increases.

6. What is a standard error?

  • An estimate of a population parameter
  • The standard deviation of a sample statistic
  • A list of all the items in the target population.
  • The probability distribution of a sample statistic

Test your knowledge: Work with sampling distributions in Python

7. Which Python function can be used to simulate random sampling?

  • pandas.DataFrame.hist()
  • pandas.DataFrame.describe()
  • pandas.DataFrame.mean()
  • pandas.DataFrame.sample()

8. Which of the following statements describe a random seed when specifying random_state in pandas.DataFrame.sample()? Select all that apply.

  • Any number can be chosen to fix the random seed.
  • The same random seed may be used over again to generate the same set of numbers.
  • Only a negative number may be chosen to fix the random seed.
  • A random seed is a starting point for generating random numbers.

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Weekly challenge 3

9. Fill in the blank: A _____ sample accurately reflects the characteristics of a population.

  • nonrepresentative
  • very small
  • biased
  • representative

10. Which of the following activities are stages in the typical sampling process? Select all that apply.

  • Perform exploratory data analysis
  • Select the sampling frame
  • Identify the target population
  • Make a point estimate of a population parameter
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