The 68-95-99.7 rule tells us 68% of the probability is between -1 standard deviation and +1 standard deviation from the mean. So we expect 75% corresponds to slightly more than 1 standard deviation.
Usually the unit normal tables don't report the area between -σ and σ but instead a cumulative probability, the area between -∞ and σ. 75% corresponds to 37.5% in each half so a cumulative probability of 50%+37.5%=87.5%. We look that up in the normal table and get σ=1.15.
So we expect 75% of normally distributed data to fall within μ-1.15σ and μ+1.15σ
That's 288.6 - 1.15(21.2) to 288.6 + 1.15(21.2)
Answer: 264.22 to 312.98
Use the following identities:
Also because the angle is in quadrant 3, sin must be negative.
Therefore
Subbing in tan = 0.958
Answer:
A
Step-by-step explanation:
this is true due to the ratio of a 30-60-90 triangle, which is 1-2-sqrt(3). The 12 corresponds to the sqrt(3), which means that the 1 corresponds to 4sqrt3 and the 2 to 8sqrt3.
:)
