一组数据有30个数，把它们分成四组，其中第一组，第二组的频数分别为7，9，第三组的频率为0.1，则第四组的频数是多少？

阅读理解。

    This is asong millions of Americans will hear this New Year's Eve. It is called Auld Lang Syne（《友谊天长地久》）. It is the traditional music played during the New Year's celebration. Auld Lang Syne is an old Scottish poem.It tells about the need to remember old friends.

The words "auld langsyne "mean" old long since". No one knows who wrote the poemfirst. However, a version by Scottish poet Robert Bums was published (出版) in 1796. The words and music we know today first appeared in a songbookthree years later.

    The songis played in the United States mainly on New Year's Eve. The version (译文) you are hearing today is by the Washington Saxophone Quartet.

    As we endour program with Auld Lang Syne. I would like to wish all of our radio friendsa very Happy New Year! This is Buddy Thomas.