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
Answer:

Step-by-step explanation:
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The population proportion have the following distribution

So under the null hypothesis the mean for the population proportion is p

And the standard deviationis given by:

Answer:
(6 , -1)
Step-by-step explanation:
2x+ y = 11 ----------------(I)
y = 11 - 2x --------------------(II)

Multiply the whole equation by 2

x - 10y = 16 --------------------(III)
Substitute y = 11- 2x in equation (III)
x - 10(11 - 2x) = 16
x - 110 + 20x = 16
21x - 110 = 16
21x = 16 +110
21x = 126
x = 126/21
x = 6
Plugin x = 6 in equation (II)
y = 11 - 2*6
y = 11 - 12
y = -1
Answer: $7.00
Step-by-step explanation:
each foot is $1, so times 7 is 7 dollars.