The figure shows four possible tongue-rolling positions used in a classroom survey. Students recorded whether they could roll their tongue into a tube or co...
Question 1 Report
The figure shows four possible tongue-rolling positions used in a classroom survey. Students recorded whether they could roll their tongue into a tube or could not do so. The teacher explained that this classroom characteristic is treated as a discontinuous category, although many human characteristics, such as height, vary continuously.
Table 1 shows the class results.
| tongue-rolling category | number of students |
|---|---|
| can roll | 21 |
| cannot roll | 15 |
(a) What type of variation is recorded in Table 1? [1]
(b) Give the percentage of students who can roll their tongue. [1]
(c) Describe why height would not be recorded using the same two boxes. [2]
(d) Give one precaution when collecting data about a human body characteristic. [1]
(e) Explain why this small class may not represent all students in the country. [1]
Answer Details
Variation that falls into separate categories is discontinuous; height is different because it can take many intermediate measured values.
- Table 1 records discontinuous variation. [1]
- \[\frac{21}{36}\times100=58.3\%\]58.3%, or 58%. [1]
- Height has many possible intermediate values. It must be measured on a scale rather than placed into only two categories. [2]
- A suitable ethical precaution is to obtain consent, keep identities confidential, or avoid pressuring students to take part. [1]
- This small class may not represent all students because the sample is small or not random, and its allele frequencies may differ from those of the wider population. [1]
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