Question

Current technology uses lasers for the inspection of solder-joint defects on printed circuit boards (PCBs). A particular manufacturer of laser-based inspection equipment claims that its product can inspect on average at least 10 solder joints per second when the joints are spaced 0.1 inch apart. The equipment was tested by a potential buyer on 30 different PCBs. In each case, the equipment was operated for exactly one second. The number of solder joints inspected on each run is found in the Homework 2.xlsx file. The potential buyer wants to know whether the sample data refute the manufacturer’s claim. Formulate appropriate hypotheses and answer with 95% confidence.

10
9
10
10
11
9
12
8
8
9
6
10
7
10
11
9
9
13
9
10
11
10
12
8
9
9
9
7
12
6

Answer 1

In this problem the claim of the manufacturer is required to check by the buyer that the equipment detects atleast 10 solder joints or not.

For this we have test fro check8nf population mean and for that we have z test but here standard deviation is unknown hence we can go for t test, these tests need data to be normal. Hence we will check normality of data. I have used a software to check this data but it can also be shown on normal probability plot paper.

The images contains the explanation and solution.