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In a line transect of length $L$ and half-width $w$, designed for estimating the density of gaur 

   , $N$ animals were counted.

The following statements represent possible assumptions about population sampling:

A. The probability of detection is independent of distance from the transect line.
B. The animals in question are uniformly distributed throughout the study area.
C. The animals are deemed to be stationary and thus detected only once during the sampling.
D. Animals on the line will be detected with a probability equal to 1.

Select the options that are considered as assumptions in line transect sampling.

Correct option is B

Line transect sampling is a widely used method for estimating animal population densities. It relies on a few fundamental assumptions to ensure unbiased and accurate estimation. Let's analyze each statement:

• Statement A: "The probability of detection is independent of distance from the transect line."

  • Incorrect. In reality, the probability of detecting an animal decreases as the distance from the transect line increases. This assumption does not hold in standard line transect sampling methods.

• Statement B: "The animals in question are uniformly distributed throughout the study area."

  • Incorrect. Animals may not always be uniformly distributed in the area. The method does not necessarily assume uniform distribution but rather considers an effective detection function.

• Statement C: "The animals are deemed to be stationary and thus detected only once during the sampling."

  • Correct. A key assumption in line transect sampling is that animals do not move significantly during the survey period, preventing double counting or missed detections due to movement.

• Statement D: "Animals on the line will be detected with a probability equal to 1."

  • Correct. This is a fundamental assumption in line transect sampling. If an animal is located directly on the transect line, it must be detected with certainty to avoid underestimating the population density.

Since statements C and D are correct assumptions of line transect sampling, the correct answer is option 2 (C and D).

Information Booster

1. Definition of Line Transect Sampling:

   • A method used in wildlife surveys where observers move along a fixed transect line and record animals detected within a specified distance.

2. Purpose of Line Transect Sampling:

   • It estimates population density using statistical models that relate the probability of detection to the distance from the transect line.

3. Detection Function in Line Transect Sampling:

   • The probability of detecting an individual decreases as the distance from the line increases. This function is modeled statistically.​