During an ecology field experiment, a group of students investigates the foraging preferences of hoverflies (Syrphidae) when presented with three different colours of artificial flowers: blue, yellow, and white.
The students place ten artificial flowers of each colour randomly across a meadow and record the total number of hoverfly visits to each flower colour over a four-hour observation period.
The recorded visits are shown in the table below:
| Flower Colour | Number of hoverfly visits |
|---|---|
| Blue | 65 |
| Yellow | 112 |
| White | 63 |
The null hypothesis formulated by the students is that there is no preference for flower colour, meaning hoverflies visit each colour with equal frequency.
Calculate the χ2 \chi^2\,χ2 value for the students' data using the formula:
χ2=∑(O−E)2E \chi^2 = \sum \frac{(O - E)^2}{E} χ2=∑E(O−E)2The critical value for χ2 \chi^2\,χ2 at the 5% significance level (p=0.05p = 0.05p=0.05) for this test is 5.991. Discuss what can be concluded from this comparison.
45 exam-style questions on OCR A A Level Biology Analysis. Each one has a worked solution and a mark scheme showing where the marks go.