Question

11.37 Researchers recorded the speed of ants on trails in their natural environment. The ants studied, Leptogenys processionalis, all have the same body size in their adult phase, which made it easy to measure speed in units of body lengths per second (bl/s). The researchers found that, when traffic is light and not congested, ant speeds vary roughly Normally, with mean 6.20 bl/s and standard deviation 1.58 bl/s.

The study described in Exercise 11.37 also reported that, when traffic is congested due to a high density of ants on the trail, ant speeds vary roughly Normally, with mean 4.64 bl/s and standard deviation 0.60 bl/s.

a.What is the probability that an ant’s speed in congested traffic is faster than 5 bl/s?

b.What percent of ant speeds in congested traffic are slower than 6 bl/s?

c. What are the 10th and 90th percentiles of ant speeds in congested traffic?

d. Draw the distributions of ant speeds in light traffic and in congested traffic on the same graph. Be sure to scale the horizontal axis, and include each distribution’s mean and standard deviation.

Answer 1