A pharmaceutical company conducted studies on a new medication for sleep apnea. The first study randomly chose 500 participants. Half of the participants were given the experimental drug, and the other half were given a placebo. Later, a second study was conducted using a random block design. First, the 500 participants were separated by gender. Then, half of the participants were randomly assigned the experimental drug or given a placebo. What improvements were demonstrated by the random block design over the completely randomized design? Explain how a matched pair design based on age would be an improvement over the random block design.