1. The following data CELLPHONE represent the digital-mode talk time in hours and the battery capacity in milliampere-hours of cell phones.
| Name |
Type |
Price |
Talk Time |
Battery Capacity |
| Samsung |
SPH-N200 CDMA |
200 |
4.5 |
800 |
| Nokia |
6185 CDMA |
99 |
4 |
1500 |
| Sanyo |
SCP-4500 CDMA |
180 |
3 |
1300 |
| Kyocera |
Smart Phone QCP-6035 CDMA |
450 |
2 |
1550 |
| Nokia |
5180 CDMA |
20 |
2.75 |
900 |
| LG TM510 |
CDMA |
130 |
1.75 |
875 |
| Audiovox |
CDM 9100 CDMA |
100 |
1.75 |
750 |
| Motorola |
V120c CDMA |
100 |
2.25 |
1100 |
| Kyocera |
QCP 2035a CDMA |
100 |
1.75 |
850 |
| Motorola |
V60c CDMA |
400 |
1.5 |
450 |
| Motorola |
Timeport O8767 CDMA |
150 |
2.25 |
900 |
| Nokia |
7160 TDMA |
130 |
2.25 |
900 |
| Nokia |
8260 TDMA |
200 |
3.25 |
900 |
| Motorola |
V2397 TDMA |
50 |
2.25 |
700 |
| Ericsson |
R278d TDMA |
100 |
2.25 |
800 |
| Ericsson |
R280LX TDMA |
195 |
2.5 |
800 |
| Nokia |
6160 TDMA |
140 |
2.25 |
900 |
| Nokia |
5160 TDMA |
140 |
2 |
900 |
a. Compute the coefficient of correlation r.
b. What conclusions can you reach about the relationship between the battery capacity and the digital-mode talk time?
c. You would expect the cell phones with higher battery capacity to have a higher talk time. Is this borne out by the data?
2. For fast food restaurants, the drive-through window is an increasing source of revenue. The chain that offers the fastest service is considered most likely to attract additional customers. In a study of drive-through times (from menu board t departure) at fast-food chains, the average time was 150 seconds for Wendy's, 167 seconds for McDonald's, 169 seconds for Checkers, 171 seconds for Burger King, and 172 seconds for Long John Silver's. Suppose the study was based on 20 customers for each fast-food chain and the following ANOVA table was developed.
SOURCE Degrees of Freedom Sum of squares Mean squares F
Among chains 4 6,536 1,634.0 12.51
Within chains 95 12,407 130.6
a. At the 0.05 level of significance, is there evidence of a difference in the average drive-through times of the five chains?
b. If appropriate, determine which fast-food chains differ in drive through times.
c. What conclusions can you reach about which fast-food chains have the best drive-through times?