Full-time ph.d. students receive an average of $12,837 per year with a standard deviation of $3000. find the probability that th
e average salary of a group of 16 randomly selected ph.d. students is more than $13,000.
1 answer:
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Answer:
see explanation
Step-by-step explanation:
(a)
x² - 2x - 4
using the method of completing the square
add/subtract ( half the coefficient of the x- term )² to x² - 2x
= x² + 2(- 1)x + 1 - 1 - 4
= (x - 1)² - 5
with c = - 1 and d = - 5
(b)
x² - 2x - 4 = 0 ← using result from (a) , that is
(x - 1)² - 5 = 0 ( add 5 to both sides )
(x - 1)² = 5 ( take the square root of both sides )
x - 1 = ± ( add 1 to both sides )
x = 1 ±