Answer:
The probability that the proportion of passed keypads is between 0.72 and 0.80 is 0.6677.
Step-by-step explanation:
According to the Central limit theorem, if from an unknown population large samples of sizes <em>n</em> > 30, are selected and the sample proportion for each sample is computed then the sampling distribution of sample proportion follows a Normal distribution.
The mean of this sampling distribution of sample proportion is:

The standard deviation of this sampling distribution of sample proportion is:

Let <em>p</em> = the proportion of keypads that pass inspection at a cell phone assembly plant.
The probability that a randomly selected cell phone keypad passes the inspection is, <em>p</em> = 0.77.
A random sample of <em>n</em> = 111 keypads is analyzed.
Then the sampling distribution of
is:

Compute the probability that the proportion of passed keypads is between 0.72 and 0.80 as follows:


Thus, the probability that the proportion of passed keypads is between 0.72 and 0.80 is 0.6677.
3(15.49 + 20.82 + 22.91)
3(59.22) =
177.66 <=== what group collected
Answer:
Maridel wants to find out how many of her classmates plan to come to the next football game. There are 800 students in her school. She selects a sample of the population by putting the names of every student into a bag and drawing out 100 names.
Which statement(s) describe her sampling method? Check all that apply.
A) Her method will produce a biased sample.
<u>B) Her method will produce a valid sample.</u>
<u>C) Her method will produce a random sample.</u>
<u>D) Her method will produce a representative sample.</u>
E) Her method will produce an invalid sample.
Step-by-step explanation:
Answer:
A is TRUE (44 in²*2=88 in²)
B is FALSE x(x-3)=88 (the rectangle) or x(x-3)/2=44 (the triangle)
C is TRUE if x(x-3)=88==>x²-3x-88=0
D is TRUE :
x²-3x-88=0
Δ=9+4*88=361=19²
==>x= 11 or x=-8 (excluded for <0)
E is FALSE for 11*4≠88
Step-by-step explanation:
correct me if i am wrong
<span>25x2 = 16
x^2 = 16/25
</span>x^2 = 4^2/5^2
<span>x = 4/5
</span>