The answer is <span> Norman Triplett
</span><span> Norman Triplett was an active cyclist who conducted on observation whether cyclists performed better if they're alone or if they're in the presence of other cyclists.
</span>As it turn out, cyclists tend to try harder on their performance if they're in the presence of other cyclists.
Answer: C.) Yang Jian, Sui dynasty
Explanation: Yang Jian took control of the Northern Dynasty. He established the Sui Dynasty and became known as Emperor Wen.
The threat to validity that is likely to occur in the scenario above is Selection Bias.
<h3>What is Selection Bias?</h3>
This occurs when a researcher has control and intentionally chooses those who are going to be researched, observed, or studied. To eliminate this bias, the scientist must ensure that the sample population is selected very randomly.
Other threats to validity are:
- History
- Maturation
- Attrition
- Social Interaction
- Instrumentation
- Testing
- Regression to the mean, etc.
Please see the link below for more about Threat to Validity:
brainly.com/question/4168290
If you are asking for the age of how old until you can do a hazardous job, i'm pretty sure the answer is 18 years old. You have to be 18 in order to do a hazardous job. If you are under that age, you cannot. But i have heard that you can do a job that is not hazardous at the age of 16 or 17. I hope this helped :)
