Answer:
171 newspapers.
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:
How many newspapers should the newsstand operator order to ensure that he runs short on no more than 20% of days
The number of newspapers must be on the 100-20 = 80th percentile. So this value if X when Z has a pvalue of 0.8. So X when Z = 0.84.
So 171 newspapers.
The slope of the line of best fit to the raw-score scatter plot is 0.98
- The equation is y = 0.98x - 3.74
- The value of y given that x = 12 is 8.02
<h3>How to determine the slope of the line?</h3>
From the question, we have the following parameters that can be used in our computation:
- Standard deviations of X, Sx = 1.88
- Standard deviations of Y, Sy =2.45
- Correlation coefficient, r between X and Y = 0.75
The slope (b) of the line is calculated as
b = r * Sy/Sx
Substitute the known values in the above equation, so, we have the following representation
b = 0.75 * 2.45/1.88
Evaluate
b = 0.98
<h3>The equation of the line of best fit</h3>
A linear equation is represented as
y = bx + c
Where
Slope = b
y-intercept = c
In (a), we have
b = 0.98
So, we have
y = 0.98x + c
Recall that the point (13, 9) is on the line of best fit.
So, we have
9 = 0.98 * 13 + c
This gives
9 = 12.74 + c
Evaluate
c = -3.74
So, we have
y = 0.98x - 3.74
<h3>The value of y from x</h3>
Here, we have
x = 12
So, we have
y = 0.98 x 12 - 3.74
Evaluate
y = 8.02
Read more about line of best fit at
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Answer:
C
Step-by-step explanation:
In this technique, if we have to factorise an expression like ax2+bx+c, we need to think of 2 numbers such that:
N1⋅N2=a⋅c=1⋅−12=−12
AND
N1+N2=b=−1
After trying out a few numbers we get N1=3 and N2=−4
3⋅−4=−12, and 3+(−4)=−1
x2−x−12=x2−4x+3x−12
x(x−4)+3(x−4)=0
(x+3)(x−4)=0
Now we equate the factors to zero.
x+3=0,x=−3
x−4=0,x=4
Answer: See attached.
Step-by-step explanation:
Answer:
x^2-y^2
Step-by-step explanation:
took a quiz and got it right
