Question 872076
Ho: u ≤ 45 (claim)
Ha: u > 45
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Sample of 20:  Sample mean = 50,  Sample SD = 3 
t(50) = (50-45)/(3/sqrt(20)) = 5/.67= 7.46
P(t > 7.46 when df = 19) = basically 0
 0 < .05  This is a 95% confidence Interval
reject manufacturer's claim at any confidence Interval