求救啊！！！哪位好心人帮帮忙啊！！！

急！！！明天考！！！求救！！！！不懂啊！！！！一点头绪都没

1） 9.4    9.9   9.9   9.9   10.0   10.2   10.2   10.5
The
mean and the standard deviation of the 8 numbers shown are 10.0 and
0.3, respectively. what percent of the 8 numbers are within 1 standard
deviation of the mean?
90%
85%
80%
75%
70%

DS
2)
Circle C and line k lies in the xy-plane. If circle C is centered at
the origin and has radius1 , does line k intersect circle C?
    1. The x-intercept of line k is greater than 1
     2. The slope of line k is -1/10.

3) If n is a positive integer and r is the remainder when n*2-1 is divided by 8, what is the value of r?
1. n is odd.
2. n is not divisible by 8