For questions 15-17, refer to the following information:Thyroid-stimulating hormone (TSH) is a hormone produced by the pituitary gland in your brain. This gland tells the thyroid to produce thyroxine (T4) and then triiodothyronine (T3) which stimulates the metabolism of almost every tissue in the human body. Using a simple blood draw, information on how the thyroid is functioning can be elucidated.

TSH level

<0.4 mU/L

Hyperthyroidism

0.4 - 4.0 mU/L

Normal

4.1 - 8.0 mU/L

Hypothyroidism

>9.0 mU/L

Extreme hypothyroidism

According to the American Thyroid Association, plasma TSH levels are normally distributed with a mean value of 3.0 mU/L and a standard deviation of 0.5 mU/L.

Approximately,how many of the 10,000 people in the study are expected to have hypothyroidism (TSH level >4.0 mU/L)? (Hint:without using the z-table, recall how observations are distributed within 1, 2, and 3 standard deviations)

The American Thyroid Association is considering to establish new criteria for hyperthyroidism which will constitute the bottom 2%. What is the cutoff TSH level for the proposed hyperthyroidism level?