Weekly challenge 5

11. Which of the following statements accurately describe the null hypothesis? Select all that apply.

  • The alternative hypothesis typically assumes that observed data occurs by chance.
  • The alternative hypothesis typically assumes that observed data does not occur by chance.
  • The null hypothesis typically assumes that observed data does not occur by chance.
  • The null hypothesis typically assumes that observed data occurs by chance.

12. What claim states that the results of a test or experiment are not explainable by chance alone?

  • P-value
  • Statistical significance
  • Confidence level
  • Significance level

13. A data professional conducts a hypothesis test. They fail to reject the null hypothesis. What statement best describes their conclusion?

  • Their p-value is greater than their significance level.
  • Their p-value is greater than their confidence level
  • Their confidence level is greater than their p-value
  • Their significance level is greater than their p-value

14. Fill in the blank: A type I error is also known as a _____.

  • false negative
  • true positive
  • false positive
  • true negative

15. Fill in the blank: Rejecting or failing to reject the null hypothesis is the _____ step in conducting a hypothesis test.

  • first
  • second
  • third
  • fourth

16. A data professional conducts a hypothesis test. They choose a significance level of 5%. They calculate a p-value of 3.3%. What conclusion should they draw?

  • Reject the alternative hypothesis.
  • Reject the null hypothesis.
  • Fail to reject the null hypothesis.
  • Fail to reject the alternative hypothesis.

17. A data professional is conducting a two-sample t-test. What does their alternative hypothesis state?

  • There is no difference between two population means.
  • There is a difference between two population proportions.
  • There is no difference between two population proportions.
  • There is a difference between two population means.

18. A data professional conducts a hypothesis test to compare the mean annual sales of two different restaurants in the same restaurant chain. They write the following code:

scipy.stats.ttest.ind(a=530, b=550, equal_var=FALSE)

What does the argument b=550 refer to?

  • Significance level
  • Observations from the second sample
  • P-value
  • Whether or not the population variance of the two samples is assumed to be equal

Shuffle Q/A 2

19. To draw a conclusion about the null hypothesis, what two concepts are compared?

  • P-value and significance level
  • Alternative hypothesis and significance level
  • Confidence level and significance level
  • P-value and alternative hypothesis

20. A data professional conducts a hypothesis test. When they draw their conclusion, they commit a type I error. Which of the following statements describe their error? Select all that apply.

  • They fail to reject a null hypothesis that is actually false.
  • They reject a null hypothesis that is actually true.
  • They conclude their result is statistically significant when in fact it occurred by chance.
  • They fail to reject a null hypothesis that is actually false.
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