An injection molder produces plastic golf tees. The process is designed to produ
ID: 3157842 • Letter: A
Question
An injection molder produces plastic golf tees. The process is designed to produce tees with a mean weight of 0.250 ounce. To investigate whether the injection molder is operating satisfactorily, 40 tees were randomly sampled from the last hour’s production. Their weights (in ounces) are listed below.
0.247
0.251
0.254
0.253
0.253
0.248
0.253
0.255
0.256
0.252
0.253
0.252
0.253
0.256
0.254
0.256
0.252
0.251
0.253
0.251
0.253
0.253
0.248
0.251
0.253
0.256
0.254
0.250
0.254
0.255
0.249
0.250
0.254
0.251
0.251
0.255
0.251
0.253
0.252
0.253
Construct a 99% confidence interval for the mean weight. Does the molder appear to be operating satisfactorily? Explain. Make clear concluding statements. Do you believe the data comes from a normally distributed population? Support your answer. Is this assumption important? Explain.
If operating correctly, the process will produce tees with a weight variance of 0.000004 oz2. Do you believe the process is operating satisfactorily in this regard? Continue with 99% confidence (or =0.01). Clearly support your results.
Confidence Interval
Test of = 0.25 vs 0.25
The assumed standard deviation = 0.00223
Variable N Mean StDev SE Mean 99% CI Z P
C1 40 0.252475 0.002230 0.000353 (0.251567, 0.253383) 7.02 0.000
Explanation / Answer
Confidence Interval
Test of ? = 0.25 vs ? 0.25
The assumed standard deviation = 0.00223
Variable N Mean StDev SE Mean 99% CI Z P
C1 40 0.252475 0.002230 0.000353 (0.251567, 0.253383) 7.02 0.000
we have the interavl that not contain 0.25 exactly so we conclude that
the process is not operationg coorectly