Answer:
A score of 150.25 is necessary to reach the 75th percentile.
Step-by-step explanation:
Problems of normal distributions can be 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.
A set of test scores is normally distributed with a mean of 130 and a standard deviation of 30.
This means that 
What score is necessary to reach the 75th percentile?
This is X when Z has a pvalue of 0.75, so X when Z = 0.675.




A score of 150.25 is necessary to reach the 75th percentile.
Answer:
1 5/9
Step-by-step explanation:
Point slope form
y-y1=m(x-x1)
slope=m
a point is (x1,y1)
slope=(y2-y1)/(x2-x1)
given
(-6,4) and (2,0)
slope=(0-4)/(2-(-6))=-4/(2+6)=-4/8=-1/2
a point is (-6,4)
x1=-6
y1=4
y-4=-1/2(x+6)
not listed
Answer:
a)
=0.89
b) 0.8413
Step-by-step explanation:
we know that




x - N(150, 20^2)

check

Answer: 3/8
Step-by-step explanation: 7/8 - 1/2= (7*2)-(1*8)
--------------- = 6/16 6 divided by 2 and then 16 divided by 2= 3/8
^8*2