Why choose quadrat positions using random coordinates across the study area?

• To pick only places with the most visible flowering plants
• To avoid choosing sites by how many plants they have
• To place every frame at the same sunny field edge

Which quadrat plan fits an estimate of the total daisies across a whole field?

• Count daisies in many randomly chosen squares
• Count daisies only along one chosen field edge
• Count daisies while moving the frame without stops

You want to compare plant counts at increasing distances from a sunny field edge into shade. Which plan fits?

• A single quadrat at the sunny edge of the site
• Random quadrats with no recorded distance from the edge
• A transect with quadrats at set distances

Random samples give a mean count of 6 plants per 1 m² quadrat in a 100 m² field. Estimate the total number of plants in the field.

Five quadrat counts are 4, 6, 5, 3 and 7. What is the mean count per quadrat?

Daisies are denser beside a pond than elsewhere in a field. A student samples only beside the pond and scales that mean to the whole field. How is the estimate likely affected?

• Likely too high for the whole field
• Likely too low because no pond plants are counted
• Exactly right because all parts have the same density

A report estimates 600 plants but does not identify the field area being estimated. Its quadrats were placed only in the densest flower patches. Which two problems should be reported?

• The plant count has no unit and quadrats must always touch
• Field area is unstated and sampling favours dense patches
• The mean cannot be used and random positions should be avoided

Two surveys use the same quadrat area and counting method in one field under the same conditions. One uses 4 independent random samples, the other 40. What is the usual benefit of 40?

• It corrects every plant missed during counting
• It removes any bias caused by poor species identification
• It usually reduces variation from chance placement