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:
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Step-by-step explanation:
Answer:
x = 25
y = 6
Step-by-step explanation:
< B = < M
2x - 20 = 30
2x = 50
<u>x = 25</u>
AB = LM
7y - 8 = 2y + 22
5y = 30
<u>y = 6</u>
Answer:
There are three kind of beta-thalassemia.
Total possible outcome= 3 types of beta- thalassemia + 1 [child will have no trace of disease] = 4
As we know Probability(outcome) = 
Probability that the child will have beta-thalassemia major =\frac{_{1}^{3}\textrm{C}}{_{1}^{4}\textrm{C}}
=
∴ favorable=
And , Total =
Probability that the child will have no trace of the disease=