Stats Car Project Paper

Submitted By jibolbo
Words: 691
Pages: 3

Bill Porter Car Watching Project
For my Project, I chose to record data of people using turn signals at a designated turn lane, and then an undesignated turn lane. On May 30, at about 5:45
p.m., along with Sanjay Khindria and Noah Shore, I sat in Luella’s and watched the cars turning across the street at the designated turn lane. Out of one hundred, 60 of them used their turn signal to make the turn. On the same day at about 7:00, with Sanjay and
Noah, I sat across the street from Ingles on Merrimon, and watched the cars turning at the 4 way stop, at the undesignated turning lane. Out of 102 cars, 60 used their turn signal. The day was very clear and sunny. The data is displayed in the two­way table below. Used Turn Signal

Did Not use Turn

Total

Signal
Designated Lane

60

40

100

Undesignated Lane 60

42

102

Total

82

202

120

When I performed a chi­square test of homogeneity of populations at a .05 confidence level, I concluded that there is no sufficient evidence suggesting that turn signal use by drivers in designated lanes is significantly different from turn signal use by drivers in undesignated lanes. I constructed a two­proportion confidence interval at a
95% confidence level to estimate the difference in the proportion of drivers who use their turn signal in a designated lane and those who use theirs in a undesignated lane.

The interval that the procedure produced was (­.1461, .12606). I then used a one­proportion confidence interval and concluded that I am 95% confident that the proportion of drivers who fail to use their turn signal in a designated lane lies within the interval of (.30398, .49602). Using the same confidence interval, with the same level of confidence, I concluded that the that I am 95% confident that the proportion of drivers who fail to use their turn signal in a undesignated lane lies within the interval of (.3136,
.5064). I used a two­proportion z test to find out if the proportion of of Ashevillians who fail to use their signal at an undesignated turn lane is significantly different from the national average, which is 25%. I concluded that the proportion of Ashevillians who fail to signal when turning at an undesignated turn lane is significantly greater than the national average. I used a two proportion z test a second time and concluded that the proportion of Ashevillians who fail to signal when turning at a designated turn lane is significantly greater than the national average.
While I was recording data at the designated turning…