Describe the Theory, Process, and Analysis of Results for Hypothesis Testing and Its Use in Evaluating a Model DATA-SCIENCE-FOUNDATIONS Practice Questions (Page 3)

Questions 11–15

1. 11expert · hard

   A data scientist is testing whether a new feature improves model recall. She uses a significance level of 0.05 and obtains a p-value of 0.06. She then decides to collect more data and reruns the test, obtaining a p-value of 0.03. What is the main concern with this approach?

   • AThe p-value of 0.03 is now significant, so the new feature is proven to improve recall.
   • BThe significance level should be changed to 0.10 to make the first result significant.
   • CCollecting more data is always a good practice and does not affect the validity of the test.
   • DCollecting more data after seeing a non-significant result increases the risk of a false positive due to repeated testing.
   Reveal Solution Discussion Select an answer first
2. 12foundation · easy

   What does 'failing to reject the null hypothesis' mean?

   • AThere is not enough evidence to conclude the alternative hypothesis is true
   • BThe alternative hypothesis is proven false
   • CThe null hypothesis is proven true
   • DThe p-value is less than the significance level
   Reveal Solution Discussion Select an answer first
4. 13application · medium

   A data scientist is planning a hypothesis test to compare the accuracy of two classification models. She wants to control the probability of incorrectly rejecting the null hypothesis. Which step in the hypothesis testing process directly addresses this?

   • ASetting the significance level (alpha) before the test.
   • BChoosing the alternative hypothesis after seeing the data.
   • CComputing the p-value and then deciding on the significance level.
   • DCollecting a large sample size to ensure the test is powerful.
   Reveal Solution Discussion Select an answer first
5. 14application · medium

   A researcher tests whether a new drug reduces blood pressure more than a placebo. The null hypothesis is that the mean reduction is the same. The p-value is 0.06, and the significance level is 0.05. What is the correct interpretation?

   • AThe alternative hypothesis is accepted because the p-value is close to 0.05.
   • BThe result is not statistically significant, so the null hypothesis is not rejected.
   • CThe null hypothesis is proven true because the p-value is high.
   • DThe result is statistically significant, so the null hypothesis is rejected.
   Reveal Solution Discussion Select an answer first
6. 15foundation · easy

   What is the role of the significance level (alpha) in a hypothesis test?

   • AIt is the maximum probability of rejecting the null hypothesis when it is actually true
   • BIt is the probability of rejecting the null hypothesis when it is actually false
   • CIt is the probability that the p-value will be less than 0.05
   • DIt is the probability of correctly accepting the null hypothesis when it is true
   Reveal Solution Discussion Select an answer first