Which of the following statements best describes “statistical significance” in the context of hypothesis testing?

A company wants to test if a new online ad campaign has increased the click-through rate (CTR) on their website. They compare the average CTR before and after the campaign launch. Which of the following would be the correct null hypothesis (H0) for this scenario?

A pharmaceutical company tests a new drug intended to lower blood pressure. The company wants to ensure the drug is effective before it goes to market, so it chooses a low alpha level. Why might the company select a lower alpha level (such as 0.01) in this test?  

A company wants to test if the mean sales of Product A are higher than the mean sales of Product B. The hypotheses are specified as follows: Null Hypothesis (H0): The mean sales of Product A are less than or equal to the mean sales of Product B. Alternative Hypothesis (Ha): The mean sales of Product A are higher than the mean sales of Product B. After conducting a one-tailed t-test, the company obtains a p-value of 0.07. Using an alpha level of 0.05, what conclusion should the company draw?

If a population has a mean of 12 and a standard deviation of [a], what’s the z-score of [b]?  Give your result to three decimal places. POST YOUR SOLUTION IN THE BOX BELOW.

Why might the median be preferred over the mean?

Which of the following quantities exhibit the behavior shown in the graph below? Screenshot 2024-11-13 at 9.12.14 PM.png

The redness of a sunset sky is evidence that

Why is the following figure not correct? delete2.png

The figure shown below is not correct. However, if you replaced the optical component by a different component, it will depict the correct phenomenon. What is that component? delete4.png