Answer:
std deviation = 1.641
Step-by-step explanation:
Given that the TSH (Thyroid Stimulating Hormone) levels among healthy individuals are normally distributed with a mean of 3.1 units/mL.
If X represents the TSH then X is N(3.1, sigma)
We do not know sigma value, but we are given that exactly 95% of healthy individuals have TSH levels below 5.8 units/mL.
We know as per standard normal distribution score that 95th percentile referes to Z score of 1.645
Using this we can find standard dev
[tex]5.8 = 3.1+1.645*standard dev\\Standard dev = \frac{5.8-3.1}{1.645} \\=1.641[/tex]