# Question: In an experiment on braking performance a tire manufacturer measured

In an experiment on braking performance, a tire manufacturer measured the stopping distance for one of its tire models. On a test track, a car made repeated stops from 60 miles per hour. Twenty tests were run, 10 each on both dry and wet pavement, with results shown in the table. (Note that actual braking distance, which takes into account the driver’s reaction time, is much longer, typically nearly 300 feet at 60 mph!)

Stopping Distance (ft)

Dry Pavement Wet Payment

145 ............ 211

152 ............ 191

141 ............ 220

143 ............ 207

131 ............ 198

148 ............ 208

126 ............ 206

140 ............ 177

135 ............ 183

133 ............ 223

a) Find a 95% confidence interval for the mean dry pavement stopping distance. Be sure to check the appropriate assumptions and conditions, and explain what your interval means.

b) Find a 95% confidence interval for the mean increase in stopping distance on wet pavement. Be sure to check the appropriate assumptions and conditions, and explain what your interval means.

Stopping Distance (ft)

Dry Pavement Wet Payment

145 ............ 211

152 ............ 191

141 ............ 220

143 ............ 207

131 ............ 198

148 ............ 208

126 ............ 206

140 ............ 177

135 ............ 183

133 ............ 223

a) Find a 95% confidence interval for the mean dry pavement stopping distance. Be sure to check the appropriate assumptions and conditions, and explain what your interval means.

b) Find a 95% confidence interval for the mean increase in stopping distance on wet pavement. Be sure to check the appropriate assumptions and conditions, and explain what your interval means.

**View Solution:**## Answer to relevant Questions

For another test of the tires in Exercise 81, the company tried them on 10 different cars, recording the stopping distance for each car on both wet and dry pavement. Results are shown in the following table. a) Find a 95% ...Using the data in Exercise 2, and assuming that the data come from a distribution that is normally distributed, a) Find a 95% confidence interval for the mean difference in page views from the two websites. b) Is 0 within ...For each of the following scenarios, say whether the data should be treated as independent or paired samples. Explain briefly. If paired, explain what the pairing involves. a) An efficiency expert claims that a new ergonomic ...The Consumer Reports article described in Exercise 23 also listed the sodium content (in mg) for the various hot dogs tested. A test of the null hypothesis that beef hot dogs and meat hot dogs don’t differ in the mean ...Suppose the specialty food chain from Exercise 26 wants to now compare the change in sales across different regions. An examination of the difference in sales over a 37-week period in a recent year for 8 stores in the state ...Post your question