[填空题]
The table below shows tu+3kmyzlt27 ev h1 ae(he distribution of trip numbers made by a8i a3. /.zl fdeok7m cbne1yo6 group of 100 taxi drivers surveyed on a working day in Syddez k/.yl o8e761.bo3amfn i cney.
1. Find
(1) the mean number of trips made by the taxi drivers; ≈
(2) the standard deviation of the number of trips made.≈
2. Find the median number of trips made by taxi drivers.
3. Find the interquartile range.
A taxi driver is chosen at random from the group of 100 taxi drivers.
4. Find the probability that this taxi driver made 13 or more trips.
A second taxi driver is chosen at random from the group of 100 taxi drivers.
5. Given that the first taxi driver chosen at random made 13 or more trips, find the probability that both taxi drivers made 14 trips.
The amount of time that the 100 taxi drivers waited for their next client was normally distributed with a mean of 15 minutes and a standard deviation of 4 minutes.≈
6. (1) Calculate the probability that a taxi driver chosen at random waited at least 12 minutes for the next client.≈
(2) Calculate the expected number of taxi drivers that waited at least 12 minutes for their next client.
The 100 taxi drivers were selected for the survey by ordering taxi identification numbers in ascending order, then selecting every 10 th number.
7. Identify the sampling technique used in this sampling method.
