1. Stats Pre and Post Course Exam
The Springfield Meteorological Center wanted to determine the accuracy of their weather forecasts. They
searched their records for those days when the forecaster had reported a 70% chance of rain. They
compared these forecasts to records of whether or not it actually rained on those particular days. The
forecast of 70% chance of rain can be considered very accurate if it rained on:
A. 95% to 100% of those days.
B. 85% to 94% of those days.
C. 75% to 84% of those days.
D. 65% to 74% of those days.
E. 55% to 64% of those days.

x coordinate can be written by using the formula, x= x1 + 2/5(x2 - x1)

step-by-step explanation:

formula

x = x1 + p/w(x2 - x1)

let the line segment ab with a(x1,y1) and b(x2,y2)

a point(x,y) divide ab in the ratio, 2: 3 the x coordinate can be written as

x = x1 + p/w(x2 - x1)

here p=2 and w = 2+3

therefore,

x coordinate can be written by using the formula, x= x1 + 2/5(x2 - x1)

similarly y coordinate y = y1 + 2/5(y2 - y1)

"standard form:

3x2 + 14x − 10 = 0

solutions based on quadratic formula:

x1   = −14 − √ 142 − 4×3×(−10) /   2×3   = −14 − 2 × √ 79 /   6   ≈ −5.296

x2   = −14 + √ 142 − 4×3×(−10) /   2×3   = −14 + 2 × √ 79 /   6   ≈ 0.629

the answer on e2020 was d.