First you have to find the square root of 90 which is about 9.5
now multiply, divide, add, or subtract 5 from 9.5 to get your answer.
Answer:9400 backpacks
Step-by-step explanation
since the number of packs to be sold in a is represented by x,
selling price for 1 week = 35x
cost price for 1 week = 15x
profit = 35x-15x = 20x
additional cost of production = 11,000
this implies that 20x - 11,000
7800
20x - 11,000
7,800
20x
7800+ 11000
20x
18,800
x
18800/2
x
9,400
at least 9,400 packs have to be sold each week to make a profit of $7800
Answer:
Step-by-step explanation:
Hello!
You have the information for two variables
X₁: Number of consumer purchases in France that were made with cash, in a sample of 120.
n₁= 120 consumer purchases
x₁= 48 cash purchases
p'₁= 48/120= 0.4
X₂: Number of consumer purchases in the US that were made with cash, in a sample of 55.
n₂= 55 consumer purchases
x₂= 24 cash purchases
p'₂= 24/55= 0.4364
You need to construct a 90% CI for the difference of proportions p₁-p₂
Using the central limit theorem you can approximate the distribution of both sample proportions p'₁ and p'₂ to normal, so the statistic to use to estimate the difference of proportions is an approximate standard normal:
[(p'₁-p'₂) ±
*
]

[(0.4-0.4364)±1.648 *
]
[-0.1689;0.0961]
The interval has a negative bond, it is ok, keep in mind that even tough proportions take values between 0 and 1, in this case, the confidence interval estimates the difference between the two proportions. It is valid for one of the bonds or the two bonds of the CI for the difference between population proportions to be negative.
I hope this helps!