Sleep in Mammals

(data input, missing values, creating variables)

1. Create a SAS data set using the sleep data set.
2. Convert the values of -999.0 to a missing value for each variable.
3. Create a new variable which is the ratio of brain weight to body weight.
4. Sort the data by this new variable and print the data set with the observation having the largest value of the ratio first.
5. Summarize the data, displaying the following quantities for each variable in the data set: number of observations, number of missing observations, minimum, median, maximum, mean and standard deviation.