Sure, let's walk through the solution step by step:
### 1.1 Identifying Variables
a) The independent variable of this investigation is:
- Altitude (m)
The independent variable is what you change in an experiment. In this case, it's the altitude, measured in meters (m).
b) The dependent variable of this investigation is:
- Average no. of red blood cells (millions per mm³)
The dependent variable is what you measure in an experiment. Here, it's the average number of red blood cells measured in millions per cubic millimeter (mm³).
### 1.2 Increasing the Validity
To increase the validity of this investigation, a scientist could:
1. Increase the sample size by measuring more individuals at each altitude.
A larger sample size would provide a more accurate representation of how altitude affects the average number of red blood cells.
2. Control other variables such as age, fitness level, and health status of the individuals to ensure they do not affect the results.
Controlling these variables ensures that the changes in the number of red blood cells are primarily due to changes in altitude and not other confounding factors.
### 1.3 Ensuring Reliability
To ensure the investigation's reliability, the scientist could:
- Repeat the measurements multiple times at each altitude and calculate the average to ensure consistency and accuracy.
This approach helps to minimize random errors and provides more consistent and reliable data.
### 1.4 Athlete Performance at High Altitudes
Possible reasons why some athletes do not perform well at high altitudes as they do at sea level include:
1. At high altitudes, the oxygen level in the air is lower, leading to less oxygen being available for muscles during performance.
With less oxygen available, muscles cannot work as efficiently, which can result in reduced performance.
2. The body might require time to acclimatize to high altitudes, which can affect performance temporarily until acclimatization occurs.
The process of acclimatization involves physiological adjustments that take time, and until the body adapts, athletic performance can suffer.
By following these steps and considerations, the investigation would not only be valid and reliable but also provide clear insights into the effects of altitude on the number of red blood cells and athletic performance.
