If the yield on the standard & Poor's Preferred Stock Index declines, how will the price of the preferred stock be affected

If the Yield on the standard & Poor's Preferred Stock Index declines, how will the price of the preferred stock be affected?

I have asked you three times:

What is the yield on the standards &poor's preferred stock index declines, how will the price of the preferred stock be affected

I have asked you three times:

What is the yield on the standards &poor's preferred stock index declines, how will the price of the preferred stock be affected