1. In a sample of 20 men, the mean height was 178 cm. In a sample of 30 women, the mean height was 164 cm. What was the mean height for both groups put together?
2. In a study of visual perception, five people were asked to estimate the length of a line by eye and then to mea- sure it with a ruler. The results, in cm, were:
By eye: 8.0, 9.0, 7.5, 9.5, 8.5
With a ruler: 8.1, 8.2, 8.1, 8.1, 8.3
a. Compute the mean measurement for each method.
b. Compute the median measurement for each method.
c. Compute the standard deviation of the measurements for each method.
d. For which method is the standard deviation the largest? Why should one expect this method to have the largest standard deviation?