Thompson and Thompson is a steel bolts manufacturing company. Their current steel bolts have a mean diameter of 137 millimeters, and a standard deviation of 8 millimeters.If a random sample of 31 steel bolts is selected, what is the probability that the sample mean would be greater than 133.5 millimeters? Round your answer to four decimal places.

See Answers (1)

Suggested Answer

Answer:The probability that the sample mean would be greater than 133.5 is 0.9926Explanation:Given:Mean = 137Standard deviation = 8Sample = 31To find the probability that the sample mean would be greater than 133.5, we have:[tex]\begin{gathered} z=\frac{X-\mu}{\frac{\sigma}{\sqrt{n}}} \\ \\ =\frac{133.5-137}{\frac{8}{\sqrt{31}}}=-2.4359 \\ \\ P(X>133.5)=1-P(z<-2.4359) \\ =1-0.0074274 \\ \approx0.9926 \end{gathered}[/tex]