Answer:
a. 68% of the workers will earn between $47300 and $69700.
b. 2.5% of workers will earn above $89000
c. Approximately 0
Step-by-step explanation:
The standard normal distribution curve in the attached graph is used to solve this question.
a. The value $47300 is a standard deviation below the mean i.e. 58500-11200=47300. While $69700 is a standard deviation above the mean. I.e. 58500+12000=69700.
Between the first deviation below and above the mean, you have 34%+34%=68% of the salary earners within this range. So we have 68%of staffs earning within this range
b. The second standard deviation above the mean is $80900. i.e. 58500+11200+11200=$80900
We have 50%+13.5%+2.5%= 97.5% earning below $80900. Therefore, 100-97.5= 2.5% of the workers earn above this amount.
c. From the Standard Deviation Rule, the probability is only about (1 -0 .997) / 2 = 0.0015 that a normal value would be more than 3 standard deviations away from its mean in one direction or the other. The probability is only 0.0002 that a normal variable would be more than 3.5 standard deviations above its mean. Any more standard deviations than that, and we generally say the probability is approximately zero.
F(x) is continuous for all x.
Pick a point and show that f(x) is either negative or positive. Pick another point and show that f(x) is negative, if positive, or positive, if negative.
At x = 30, f(30) - 1000 = 900 + 10sin(30) - 1000 ≤ 0
Now, show at another point f(x) - 1000 is positive, and hence, there would be root between 30 and such point.
Let's pick 40.
At x = 40, f(40) - 1000 = 1600 + 10sin(40) - 1000 ≥ 0
Since f(x) - 1000 is continuous, there lies a root between 30 and 40, and hence, 30 ≤ c ≤ 40
( a ) The system of equations:
2 r + b = 8.403 r + b = 9.35( b ) Graph is in the attachment.
( c ) Each item costs:
b = $6.50, r = $0.95We can prove it: 2 * 0.95 + 6.50 = 8.40
3* 0.95 + 6.50 = 9.35
(x) = arcsec(x) − 8x
f'(x) = d/dx( arcsec(x) −
8x )
<span> 1/xsqrt( x^2 - 1) - 8</span>
f'(x) = 0
1/xsqrt( x^2 - 1) - 8 = 0
8 x sqrt (x^2-1) = 1
<span> ( 8 x sqrt (x^2-1) )^2 = 1</span>
64 x^2 ( x^2 - 1) = 1
64 x^4 - 64 x^2 =1
64 x^4 - 64 x^2 - 1 = 0
x = 1.00766 , - 1.00766
<span> x = - 1.00766</span>
f(- 1.00766) = arcsec(-
1.00766) − 8( - 1.00766)
f( - 1.00766 ) = 11.07949
x = 1.00766
f(1.00766) =
arcsec(1.00766) − 8( 1.00766)
f(1.00766 ) = -7.93790
relative maximum (x, y) =
(- 1.00766 , 11.07949 ) relative minimum (x, y) = ( 1.00766 ,
-7.93790 )
