Answer:
A perfect score on a test
Step-by-step explanation:
Since the score gets subtracted for each wrong answer, if x=0 then then nothing would get taken away from the initial 80
Given:
Sample size, n = 40
Sample mean, xb = $6.88
Population std. deviation, σ = $1.92 (known)
Confidence interval = 90%
Assume normal distribution for the population.
The confidence interval is
(xb + 1.645*(σ/√n), xb - 1.645*(σ/√n)
= (6.88 + (1.645*1.92)/√40, 6.88 - (1.645*1.92)/√40)
= (7.38, 6.38)
Answer: The 90% confidence interval is (7.38, 6.38)
Number one is true glaciers do store 75% of the worlds fresh watet
Answer:
−π
----
4
Step-by-step explanation:
Alright, archtan /
tan
−
1
(
x
)
is the inverse of tangent. Tan is
sin
cos
. Like the inverse of sin, the inverse of tan is also restricted to quadrants 1 and 4.
Knowing this we are solving for the inverse of tan -1. We are basically being asked the question what angle/radian does tan(-1) equal. Using the unit circle we can see that tan(1)= pi/4.
Since the "Odds and Evens Identity" states that tan(-x) = -tan(x). Tan(-1)= -pi/4.
Knowing that tan is negative in quadrants 2 and 4. the answer is in either of those two quadrants. BUT!!! since inverse of tan is restricted to quadrants 1 and 4 we are left with the only answer -pi/4.
