- IB
- Question Type 3: Initiating the chi-squared independence test with the hypothesis and critical regions
An email campaign’s response is recorded by customer segment (New, Returning, VIP) and action (Open, Click). Observed counts are given. For the chi-squared test of independence, state , , compute degrees of freedom, and specify the critical region at the 10% significance level.
A health study records smoking status (Smoker, Non-smoker) and presence of a condition (Present, Absent). Counts: Smoker — 42 present, 58 absent; Non-smoker — 30 present, 90 absent. For a chi-squared independence test, provide , , the degrees of freedom, and the critical region at the 1% significance level.
Website visitors are grouped by device (Mobile, Desktop) and browser (Chrome, Safari, Firefox, Other). Counts: Mobile — 180, 60, 30, 30; Desktop — 90, 45, 35, 20. State , , the degrees of freedom, and the critical region at the 10% significance level for a chi-squared test of independence.
Purchases are categorized by region (North, East, South, West) and payment method (Card, Cash). Counts: North — 45, 20; East — 30, 15; South — 28, 22; West — 25, 18. For a chi-squared test of independence, give , , the degrees of freedom, and the critical region at the 5% level.
Commuters are classified by travel mode (Car, Bus, Train) and time of travel (Peak, Off-peak). Observed counts: Peak — Car 62, Bus 25, Train 33; Off-peak — Car 38, Bus 30, Train 22. For a chi-squared test of independence, state , , the degrees of freedom, and the critical region at the 10% significance level.
Students are grouped by education level (High school, Undergraduate, Postgraduate) and preferred streaming platform (A, B, C). Observed counts: HS — 24, 18, 8; UG — 31, 27, 12; PG — 15, 16, 11. Initiate a chi-squared independence test: state , , degrees of freedom, and the critical region at the 1% significance level.
Employees are classified by department (Sales, HR, Engineering, Support, Finance) and training completion status (Completed, Not completed, In progress). Sample counts are recorded in a table. For a chi-squared test of independence, state , , compute the degrees of freedom, and specify the critical region at the 5% significance level.