两样本均数比较（双侧）的t检验，检验统计量t＝1.45，a＝0.05统计推断为（）A
题型：单项选择题
问题：
两样本均数比较（双侧）的t检验，检验统计量t＝1.45，a＝0.05统计推断为（）
A．两样本均数的差别有显著性
B．两总体均数的差别有显著性
C．两样本均数的差别无显著性
D．两总体均数的差别无显著性
E．本题未给出自由度，所以还不能进行、
题型：单项选择题
阅读理解
In 1901, the citizens of Colorado Springs in the USA decided to collect everyday items and to
seal (封住)them in a special box. The box was marked "To be opened after midnight, December 31st,
AD 2000",and was kept in the Colorado College Library.
One hundred years later, on the appointed (约定)day, 300 people gathered to watch the opening
of the box. Many in the crowd were the descendants (后代)of people who had placed things inside the
box.
When the box was opened after midnight, the things inside the box were in very good condition.
There were newspapers, photos, diaries, name cards, family trees, books and lots of letters, including
one written by Theodore Roosevelt, who became the President of the USA later that year. One of
Roosevelt's friends lived in Colorado Springs at that time.
Many of the letters were written to their descendants. They describe the hopes that the people of
1901 had for the people of the next century. At that time, Colorado Springs had just a few thousand
people. Now nearly half a million people live there.
Colorado College Library has scanned the materials and put them on a website. Cecil Muller,
whose grandfather had placed a collection of postcards in the box, said that the time capsule was a
great treasure. "This is a wonderful educational resource(资源). We can learn so much about our
history,"he said. "I never knew my grandfather, but now I feel very close to him. "
1. According to the passage, "time capsule" means ______.
A. a collection of clocks and wat
ches
B. a machine for travelling through time
C. a collection of items for people to look at in the future
D. a collection of unwanted items
2. Many of the letters in the time capsule talked about.
A. the history of the town
B. the people who lived in the town
C. the politics of the USA
D. people's hopes for the future
3. Cecil Muller says that the time capsule ______.
A.helps him to get to know his grandfather
B. is worth a lot of money
C. brings back his memories of his grandfather
D. helps him to remember his younger day