The gross profit margin is calculated using the following rule:
gross profit margin = total profit / total sales
Now, we need to get the values of total profit and total sale:
total profit = <span>9*8-(40+8)=24$
total sales = 9*8 = 72$
Now, we will substitute in the above equation:
gross profit margin = 24/72 = 1/3 = 0.3333334
% = 0.33333334*100 = 33.3334%</span>
Using the binomial distribution, it is found that there is a 0.5 = 50% probability of selecting a two-child family with one boy and one girl.
For each child, there are only two possible outcomes, either it is a boy, or it is a girl. The probability of a child being a boy or being a girl is independent of any other child, which means that the binomial distribution is used to solve this question.
Binomial probability distribution
The parameters are:
- x is the number of successes.
- n is the number of trials.
- p is the probability of a success on a single trial.
In this problem:
- Two children, hence
. - Equally as likely to be a boy or a girl, hence
.
The probability of one of each is P(X = 1), hence:


0.5 = 50% probability of selecting a two-child family with one boy and one girl.
A similar problem is given at brainly.com/question/24863377
<h2>
Answer with explanation:</h2>
Confidence interval for mean, when population standard deviation is unknown:

, where
= sample mean
n= sample size
s= sample standard deviation
= Critical t-value for n-1 degrees of freedom
We assume the population has a normal distribution.
Given, n= 19 , s= 3.8 , 

A) Critical t value for
and degree of 18 freedom
= 2.8784
B) Required confidence interval:

Lower bound = 19.9 years
Uppen bound = 24.9 years
C) Interpretation: We are 99% confident that the true population mean of lies in (19.9, 24.9) .