Roberta has collected a set of data and calculated the mean to be 34. The set contains 75 numbers, but Roberta gets an email telling her to add the following 5 numbers to her data: {23, 26, 32, 33, 40}

To the nearest tenth, what is the new mean for her data?
A) 27.8
B) 30.8
C) 33.8
D) 36.8

Question

Roberta has collected a set of data and calculated the mean to be 34. The set contains 75 numbers, but Roberta gets an email telling her to add the following 5 numbers to her data: {23, 26, 32, 33, 40}

To the nearest tenth, what is the new mean for her data?
	A) 	27.8 	
	B) 	30.8 	
	C) 	33.8 	
	D) 	36.8

123ab456c · Answer

Remember how the mean is calculated:
sum of valuesnumber of values
Therefore, you know that:
sum of values75=34
Now you must add in 5 more values.  Isolate the sum of values to left first:
sum of values=(34)(75)=2550
Now add in the new values and recalculate the mean:
2550+23+26+32+33+4080=?