The null hypothesis must be rejected as there is enough evidence that the diameter differs from 0.5 inches.
Given values are
The population mean is 0.5 inches
The Null hypothesis is : H₀ : μ = 0.5 inches
The Alternative hypothesis is given by Hₐ : μ ≠ 0.5 inches
Now let us consider the parameter given:
sample size is n = 15
test statistics is t = 1.66
The level of significance : α = 0.05
The degree of freedom: df = n-1 = 15 -1 =14
Calculating the critical value : [tex]t_\frac{\alpha}{2} ,df[/tex] = 2.145
We are using the critical value of [tex]t_\frac{\alpha}{2}[/tex] as the test is one-tailed .
Comparing the value of t and [tex]t_\frac{\alpha}{2}[/tex] we can see that : [tex]t < t_\frac{\alpha}{2}[/tex]
Hence the null hypothesis can be rejected.
Given that the value of t does not fall within the range covered by (i.e., the range from -2.145 to the bottom of the normal distribution curve), we are unable to reject the null hypothesis.
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