Ran Wang
0786512
2/12/2014
Chapter 3
1. The content of liquid detergent bottles is being analyzed, Twelve bottles, randomly selected from the process, are measured, and the results are as follows (in fluid ounces): 16.05, 16.03, 16.02, 16.04, 16.05, 16.01, 16.02, 16.02, 16.03, 16.01, 16.00, 16.07
(a) Calculate the sample average.
(16.05+16.03+16.02+16.04+16.05+16.01+16.02+16.02+16.03+16.01+16+16.07)/12=16.03
(b) Calculate the sample standard deviation.
=0.0193
3.2. The bore diameters of eight randomly selected bearings are shown here (in mm): 50.001, 50.002, 49.998, 50.006, 50.005, 49.996, 50.003, 50.004
(a) Calculate the sample average.
(50.001+50.002+ 49.998+50.006+50.005+49.996+50.003+50.004)/8=50.001
(b) Calculate the sample standard deviation.
=3.2186
3.4. Consider the furnace temperature data in Exercise 3.3 (The nine measurements that follow are furnace temperatures recorded on successive batches in a semiconductor manufacturing process (units are °F): 953, 955, 948, 951, 957, 949, 954, 950, 959)
(a) Find the sample median of these data.
It's 953.
(b) How much could the largest temperature measurement increase without changing the sample median? It will not change the sample median anyway when we increase the largest temperature measurement.
3.6. The time to failure in hours of an electronic component subjected to an accelerated life test is shown in Table 3E.1. To accelerate the failure test, the units were tested at an elevated temperature (read down, then across).
■ T A B L E 3 E . 1
Electronic Component Failure Time
127 124 121 118
125 123 136 131
131 120 140 125
124 119 137 133
129 128 125 141
121 133 124 125
142 137 128 140
151 124 129 131
160 142 130 129
125 123 122 126
(a) Calculate the sample average and standard deviation.
According to excel, average is 129.975 and standard deviation is 8.914.
(b) Construct a histogram.
(c) Construct a stem-and-leaf plot.
stem leaf 11
8 9
12
0 1 1 2 3 3 4 4 4 4 5 5 5 5 5 6 7 8 8 9 9
13
0 1 1 1