The cooling system in a nuclear submarine consists of an ass

The cooling system in a nuclear submarine consists of an assembly of welded pipes through which a coolant is circulated. Specifications require that weld strength must meet or exceed 15o psi. Ca Suppose that the design engineers decide to test the hypothesis Ho: u 150 versus H1: u 150. Explain why this choice of alternative hypothesis is better than H1: u 150. (b)A random sample of 20 welds results in X 157.65 psi and s 12.39 psi. What conclusions can you draw about the hypothesis in part (a)? State any necessary assumptions about the underlying distribution of the data. Use the p-value approach

Solution

Because our claim is to check whether average >150 alternate hypothesis should be

mu>150

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b) n = Sample size = 20

The assumptions underlying are

i. Sample is random

ii. Sample represents the population

As p value <0.01, reject null hypothesis at 1% sign. level.

n	20
x bar	157.65
sigma	12.39
std error	2.770488
As n<30, t test is used.
t	diff/std error
t	2.761246
df	26-1	25
p	0.005316