We need to find out how many adults must the brand manager survey in order to be 90% confident that his estimate is within five percentage points of the true population percentage.
From the given data we know that our confidence level is 90%. From Standard Normal Table we know that the critical level at 90% confidence level is 1.645. In other words, 
.
We also know that E=5% or E=0.05
Also, since, 
is not given, we will assume that =0.5. This is because, the formula that we use will have 
in the expression and that will be maximum only when =0.5. (For any other value of , we will get a value less than 0.25. For example if, is 0.4, then 
and thus, 
.).
We will now use the formula
We will now substitute all the data that we have and we will get
which can approximated to n=271.
So, the brand manager needs a sample size of 271
The answer is 4/6 which can be reduced to 2/3.
5’3 is 63 inches since her brother is 1/3 larger so 63/3= 21 inches
A and b can do a piece of work in 12 days. If a alone have to finish the job among b and c so
A and b=12
A (24 days alone without b)
So if b and c 15 days and c 20 days. If a have to do all I would add 24 and 15 and 20 which would be 59 days
Step-by-step explanation:
sorry i couldn't solve the last and the last second one
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