Calculate this z test statistic and enter your answer, correct to 3 decimal places, into the box below.
New Zealand requires cyclists to wear cycle helmets on public roads and this is enforced with fines. Most other countries have no mandatory helmet law, and a few have a law but do not enforce it. Finland is an example of a country that has a mandatory cycle helmet law but does not enforce it.
A road safety researcher is interested in whether the proportion of cyclists in New Zealand do actually wear helmets is different to the proportion of cyclists in Finland who wear helmets. She has data from a survey which gives the following information:
New Zealand: Of 210 New Zealand cyclists surveyed, 100 wear a helmet while cycling.
Finland: Of 630 Finnish cyclists surveyed, 290 wear a helmet while cycling.
Say that the true population proportion of New Zealand cyclists who wear a helmet is p1 and the true population proportion of Finnish cyclists who wear a helmet is p2.
If our null hypothesis is H0: p1 - p2 = 0 and our alternative hypothesis is Ha: p1 - p2 ≠ 0, what is the z test statistic for testing the difference p1 - p2?
Calculate this z test statistic and enter your answer, correct to 3 decimal places, into the box below.
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