Answer:
A sample size of 657 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of 
, and a confidence level of 
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of 
.
The margin of error is:
95% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
In the past, 19% of all homes with a stay-at-home parent had the father as the stay-at-home parent.
This means that 
(a) What sample size is needed if the research firm's goal is to estimate the current proportion of homes with a stay-at-home parent in which the father is the stay-at-home parent with a margin of error of 0.03?
A sample size of n is needed.
n is found when 
Then
Rounding up to the nearest whole number.
A sample size of 657 is needed.
Let <em>X</em> be the random variable representing the amount (in grams) of nicotine contained in a randomly chosen cigarette.
P(<em>X</em> ≤ 0.37) = P((<em>X</em> - 0.954)/0.292 ≤ (0.37 - 0.954)/0.292) = P(<em>Z</em> ≤ -2)
where <em>Z</em> follows the standard normal distribution with mean 0 and standard deviation 1. (We just transform <em>X</em> to <em>Z</em> using the rule <em>Z</em> = (<em>X</em> - mean(<em>X</em>))/sd(<em>X</em>).)
Given the required precision for this probability, you should consult a calculator or appropriate <em>z</em>-score table. You would find that
P(<em>Z</em> ≤ -2) ≈ 0.0228
You can also estimate this probabilty using the empirical or 68-95-99.7 rule, which says that approximately 95% of any normal distribution lies within 2 standard deviations of the mean. This is to say,
P(-2 ≤ <em>Z</em> ≤ 2) ≈ 0.95
which means
P(<em>Z</em> ≤ -2 or <em>Z</em> ≥ 2) ≈ 1 - 0.95 = 0.05
The normal distribution is symmetric, so this means
P(<em>Z</em> ≤ -2) ≈ 1/2 × 0.05 = 0.025
which is indeed pretty close to what we found earlier.
Answer:
the answer is 36 gallon
Step-by-step explanation:
Answer: y−3=−3y−43
Step 1: Add 3y to both sides.
y−3+3y=−3y−43+3y
4y−3=−43
Step 2: Add 3 to both sides.
4y−3+3=−43+3
4y=−40
Step 3: Divide both sides by 4.
4y
4
=
−40
4
y=−10
Answer:
y=−10
Step-by-step explanation: brainliest:)
Answer:
The answer is C.
Step-by-step explanation:
It cannot be between 3 and 4 because 2/3 is less than 1. You cannot end up with a larger number than 3 in this case. Similarly, it cannot be less than 2/3 because you are multiplying it by 3, which is larger than your first number.
Therefore, it has to be between 3 and 2/3 because you are taking two thirds of 3, which is 2.
