Your method is right so u already know how to do it
        
             
        
        
        
Answer: The standard error of the mean = 0.5
Step-by-step explanation:
Given : Sample size : n =  144
Standard deviation : 
The formula to find the standard error of the mean is given by :-

i.e. 
Hence, the standard error of the mean =0.5
 
        
             
        
        
        
6 ft= 6x12in= 72 in.
8 ft= 8x12in= 96 in.
12ft=12x12in=144 in
25ft=25x12in=300 in
50ft=50x12in=600 in
72 in, 96 in, 96 in, 144 in, 300 in, 300 in, 600 in
Mean= (72+96+96+144+300+300+600)÷7
1608÷7 = 229.7 inches
Median=middle value in set = 144 inches
Mode= value(s) tha occur most often = 96 inches and 300 inches
Range=difference of largest and smallest values in set = 600-72= 528
Choice A
        
                    
             
        
        
        
Answer: (4a - 3b)2
Step-by-step explanation:it stays the same because there is no like terms