Practice 6.1.3. State that the statistic standard deviation is used to summarize the spread of values around the mean, and that within a normal distribution approximately 68% and 95% of the values fall within plus or minus one or two standard deviations respectively. with authentic IB Sports, exercise and health science (SEHS - Old) exam questions for both SL and HL students. This question bank mirrors Paper 1, 2, 3 structure, covering key topics like core principles, advanced applications, and practical problem-solving. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
A statistical analysis determined that the average professional rower could maintain an average power output of 6.0 watts per kilogram (W kg–1), with a standard deviation of 0.5 W kg–1. What proportion of the total data spread would fall within the range of 5.0–7.0 W kg–1?
What percentage of the normal distribution lies within ±1 standard deviation of the mean?
What does standard deviation represent?
A study examined how three different sports influenced force–time variables during a vertical jump performed by elite athletes.
The measured variables included the time spent in the eccentric phase (when the quadriceps lengthen in preparation for the jump), the total duration of the jump (including both eccentric and concentric phases), the rate of force development during the eccentric phase, and the height of the jump.
Table 1: Average and standard deviation (SD) for the force–time variable measurements
| Sport | Eccentric time (ms) | Total jump time (ms) | Eccentric rate of force development (kN s⁻¹) | Jump height (cm) |
|---|---|---|---|---|
| Volleyball | 260 (7) | 494 (9) | 3.37 (0.12) | 46.8 (12.7) |
| Soccer | 199 (5) | 485 (10) | 4.53 (0.16) | 50.1 (15.9) |
| Rugby | 241 (8) | 495 (2) | 5.41 (0.10) | 45.7 (11.8) |
Identify the sport with the greatest mean jump height.
Identify the sport with the smallest standard deviation for eccentric rate of force development.
Using the data from Table 1, analyse the differences in force–time variables for volleyball, soccer and rugby players.
Calculate the difference between mean eccentric rate of force development for rugby and volleyball.
Comment on the meaning of the standard deviation with reference to Table 1.