F.3 math

1.find the mean,median and mode(1-4)

1. 2,2,2,3,3,5,5,8

mean: 3.75 ｛(2+2+2+3+3+5+5+8)/8 = 3.75｝
median: 3 ｛第(8+1)/2個數，即係第4.5個數，即係(3+3)/2 = 3｝
mode: 2 ｛2出現得最多｝


2. 2,7,5,10,6,10,1,4

mean: 5.625
median: 5.5
mode: 10


3. 0,5,7,-3,4,-2,7,1,9,5

mean: 3.3
median: 4.5
mode: cannot be found ｛5同7出現次數相同｝


4. 31,40,51,67,41,53,39,42

mean: 45.5
median: 41.5
mode: cannot be found ｛所有number出現次數相同｝



2.Consider the following date which are arranged in ascending order.
1,2,a,6,8,9
If the median of the data is 5,find the value of a.

Ans：
(a+6)/2=5
a+6=10
a=4



3.The average height of 6 students is 166cm.If their heights are 167cm,172cm,
158cm,161cm,162cm and h cm respectively,find the value of h.

Ans：
(h+167+172+158+161+162)/6=166
h+167+172+158+161+162=996
h=176




4.Given that the median of the following data is 22.(Assume the data is in
ascending order.)
10,10,y-12,y,y,25,50,3y,70,20
^^^^(其實個order好似錯左，20唔應該系70後面)

a.Find the mean and the mode.
b.If a datum is removed randomly,find the probability that the mode remains
unchanged.

（因為你個題目有問題，所以幫唔到你）