Answer:
a) Mean = 382.3 psi
Standard deviation = 20.8 psi
b) 392.7 psi
c) P(X<400)=0.8026
Step-by-step explanation:
a) The population mean can be estimated as equal to the mean of the sample, and the population standard deviation can be estimated from the sample standard deviation:
b) We start by searching for the z-value for the 95th percentile. This value is
z=1.645:
Then, the strength value below which 95% of all welds will have their strengths is:
c) We calculate the probability of X being equal or less than 400 as:
Answer:
try 10x + y = 9/7
Step-by-step explanation:
The 7th term of the geometric sequence is 8,192!
Answer:
NF = 25
Step-by-step explanation:
Since ∆NKF ~ ∆LZF, the ratio of their corresponding side lengths would also be the same.
This means that:
KF/ZF = NF/LF
KF = x + 3
ZF = 4
NF = 15 + x + 3 = x + 18
LF = x + 3
Plug in the values into the equation
(x + 3)/4 = (x + 18)/(x + 3)
Cross multiply
(x + 3)(x + 3) = (x + 18)(4)
x² + 3x + 3x + 9 = 4x + 72
x² + 6x + 9 = 4x + 72
x² + 6x + 9 - 4x - 72 = 0
x² + 2x - 63 = 0
Factorize to find x
x² + 9x - 7x - 63 = 0
x(x + 9) -7(x + 9) = 0
(x + 9)(x - 7) = 0
x + 9 = 0 or x - 7 = 0
x = -9 or x = 7
We'd use the positive value of x, which is 7.
Therefore, x = 7.
✅NF = 15 + (x + 3)
Plug in the value of x
NF = 15 + (7 + 3) = 15 + 10
NF = 25
