Answer:
1. y = - 4 x + 5
2. x = -8
Step-by-step explanation:
1. (-1,9) (1,1)
y = mx + b
m = (y-y') / (x-x') = (1-9) / (1-(-1)) = -8 / 2 = - 4
b = y - mx = 9 - (-4) x (-1) = 5
equation: y = - 4 x + 5
check: (1,1) y=1 = (-4) x 1 + 5 = 1
2. Vertical line through (-8,6) is a line perpendicular to x axis
x = -8
Answer:
62.17% probability that a randomly selected exam will require more than 15 minutes to grade
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
What is the probability that a randomly selected exam will require more than 15 minutes to grade
This is 1 subtracted by the pvalue of Z when X = 15. So
has a pvalue of 0.3783.
1 - 0.3783 = 0.6217
62.17% probability that a randomly selected exam will require more than 15 minutes to grade