120 pupils went on a feildtrip . 55% of the pupils were girls and the rest were boys. How many boys went on the trip?
2 answers:
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Answer: 650
Step-by-step explanation:
When prior estimate of population proportion is known , then the formula to find the required sample size is given by :-
, where p= population proportion
E= margin of error
z* = Critical value.
Let p be the proportion of adults able to identify a Toyota Scion by brand and model name.
As per given , we have
p = 12%= 0.12
E= 2.5%=0.025
Critical value for 95% confidence interval : z* = 1.960 [By z-table ]
Then, the required sample size =
Thus , the required sample size = 650