Discussion:
Q1. The Randolph Corporation is planning to replace its Alpha Machine with a newer Beta Machine. Before the replacement of Alpha takes place, the company decides to run parallel productions to see if the Beta Machine actually reduces production times. The production time results for the two machines follow.
Use Excel to determine if the Beta machine significantly reduces production time. Use a .05 level of significance.
Alpha Machine Beta Machine
2.30 2.34 2.34 2.22 2.21 2.18
2.33 2.30 2.30 2.19 2.21 2.21
2.29 2.30 2.33 2.18 2.15 2.17
2.28 2.31 2.34 2.23 2.19 2.19
2.27 2.33 2.31 2.24 2.18 2.21
2.30 2.28 2.31 2.19 2.21 2.18
2.31 2.33 2.27 2.19 2.18 2.22
2.30 2.33 2.29 2.20 2.18 2.23
2.30 2.29 2.33 2.20 2.21 2.19
2.30 2.29 2.30 2.13 2.18 2.15
Q2. The Weaver Company manufactures baskets. The company selects a sample of five workers and sends them through a new Basket Weaving training program. The daily production rates for the sample of factory workers before and after the training program are shown below.
Worker Before After
1 7 10
2 11 13
3 10 11
4 9 12
5 9 11
At a .05 level of significance, use Excel to test to see if the training program was effective. That is, did the training program actually increase the production rates?
Q3. Play Kidz has three stores located in three different areas. Random samples of the sales of the three stores (in thousands) are shown below.
Store A Store B Store C
80 84 81
81 86 85
76 82 86
83 80
80
At a .05 level of significance, use Excel to test to see if there is a significant difference in the average sales of the three stores.
4. During the 2005 "sweeps week", the viewing audience was distributed as follows: 36% NBC, 22% ABC, 24% CBS, and 18% FOX. During the current year's "sweeps week" a sample of 50 homes yielded the following data. Use Excel to test at α= .05 to determine if the audience proportions have changed.
NBC FOX ABC FOX ABC ABC CBS NBC FOX FOX
ABC ABC CBS ABC NBC NBC NBC CBS FOX ABC
ABC FOX NBC CBS CBS NBC NBC ABC FOX FOX
NBC NBC NBC NBC FOX ABC FOX NBC FOX CBS
CBS CBS FOX FOX NBC CBS FOX CBS NBC FOX