IB skill practice

Use two-proportion z statistics

Calculate the z statistic for a difference between two proportions.

Paper 1, Paper 2 5 marks Difficulty 4

Use two-proportion z statistics - exam scenario

Confirm the modelling meaning first. A renewable-energy team compares two sample proportions: \(\hat p_1=0.59\), \(n_1=132\), \(\hat p_2=0.47\), \(n_2=119\). Using the pooled proportion, calculate the z statistic. Enter the requested value and choose the interpretation that matches the result.

Worked practice: result and interpretation

Calculate the requested result first, then choose the interpretation that follows from it.