Question

Current technology uses high-resolution X-rays and lasers for inspection of solder-joint defects on printed circuit boards. A particular manufacturers 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 .1 inch apart. The equipment was tested by a potential buyer on 48 different PCBs. In each case, the equipment was operated for exactly 1 second. The results of the Mini-tab analysis on the number of solder-joints inspected on each of the 48 PCBs is shown below. The sample standard deviation was used as an estimate of $\sigma$ as the sample size was greater than 30.

One- Sample Z: Inspected

Descriptive Statistics

N	Mean	StDev	SE Mean	95% Upper Bound for $\mu$
48	9.292	2.103	.304	.9791

$\mu$: mean of inspected

Known standard deviation = 2.103

Test

Null hypothesis H0: $\mu$=10

Alternative Hypothesis H₁: $\mu$ < 10

Z-Value	P- Value
- 2.33	.010

Using an Alpha of .05 and the p-value method, what decision and conclusion should be reached? Choose One.

A. As the p-value of .01 is less than the alpha of .05, we fail to reject the null hypothesis. We conclude that the true mean number of solder joints inspected by this laser-based inspection equipment is not significantly greater than 10 solder- joint inspections per second. The data refutes the manufacturer's claim.

B. As the p-value of .01 is less than the alpha of .05, we reject the null hypothesis. We conclude that the true mean number of solder joints inspected by this laser-based inspection equipment is significantly greater than 10 solder-join inspections per second. The data does not refute the manufactures claim.

C. As the p-value of .01 is less than the alpha of ,05, we reject the null hypothesis. We conclude that the true mean number of solder joints inspected by this laser-based inspection equipment is significantly less than 10 solder-joint inspects per second. The data refutes the manufacturer's claim.

D. As the p-value of .01 is less than the alpha of .05, we fail to reject the null hypothesis. We conclude that the true mean number of solder joints inspected by this laser-based inspection equipment is not significantly less than 10 solder-joint inspections per second. The data does not refute the manufacturer's claim.

Answer 1