Question 412073
The incubation time for Rhode Island Red chicks is normally distributed with a mean of 21 days (μ) and standard deviation (σ) of approximately 1 day. If 1000 eggs are being incubated, how many chicks do we expect will hatch? 
(a) In 19 to 23 days?
z(19) = (19-21)/1 = -2
z(23) = (23-21)/1 = 2
P(19 <= x <= 23) = P(-2 <= z <= 2) = 0.9545
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(b) 21 days or few?
P(x <= 21) = P(z <= 2) = normalcdf(-100,2) = 0.9773
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Cheers,
Stan H.
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Format that I can understand is below: 
Z = x–&#956; = 
&#963; 
Change (Z to X)(To checking and verifying information)
X = Z &#963; + &#956; X = (?.00)(1) + 21 (X =??)