4. Data & Probability

Stat Inference — Quiz

Test your understanding of stat inference with 5 practice questions.

Practice Questions

Question 1

A researcher wants to estimate the average height of all adult males in a city. They randomly select 50 adult males from a local gym and measure their heights. Which of the following statements best describes the potential for selection bias in this sampling method?

Question 2

A political pollster wants to estimate the proportion of voters who support a particular candidate. They conduct a telephone survey, but only call landlines. Which type of bias is most likely to be introduced by this sampling method?

Question 3

A company is testing a new energy drink. They give the drink to one group of employees and a placebo (a drink with no active ingredients) to another group. Both groups are unaware of what they are receiving. What is the primary reason for using a placebo in this experimental design?

Question 4

A researcher wants to investigate the relationship between the number of hours a student spends studying per week ($x$) and their GPA ($y$). They collect data from a random sample of 200 university students and calculate a correlation coefficient of $r = 0.75$. Based on this finding, what informal statistical inference can be made?

Question 5

A school district wants to estimate the proportion of its high school students who participate in at least one extracurricular activity. They randomly select 5 high schools within the district and then survey every student in those 5 selected high schools. What type of sampling method is this?