SOLUTION: size : 10,12,14,16,18,20 frequency: 3,7,?,20,8,5 mean is 15 find the missing frequency

Algebra ->  Probability-and-statistics -> SOLUTION: size : 10,12,14,16,18,20 frequency: 3,7,?,20,8,5 mean is 15 find the missing frequency      Log On


   

Question 1206038: size : 10,12,14,16,18,20
frequency: 3,7,?,20,8,5
mean is 15 find the missing frequency
Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

x = the missing frequency value

Given data
Size101214161820
Frequency37x2085


Or we can format the table like this
SizeFrequency
103
127
14x
1620
188
205


Multiply each size with its paired frequency. Then add up the results.
10*3 + 12*7 + 14*x + 16*20 + 18*8 + 20*5 = 14x+678

This is then divided over the total frequency (3+7+x+20+8+5 = x+43) to determine the mean.

mean = (14x+678)/(x+43) = 15
(14x+678)/(x+43) = 15
14x+678 = 15(x+43)
14x+678 = 15x+645
678-645 = 15x-14x
33 = x
x = 33


Answer: 33