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.
Answer:
p=0.063
Step-by-step explanation:
Let X be number of the certain brand of jelly beans that are made so that each package contains about the same number of beans.
X is N(375, 8)
YOu are collecting a sample size of
n = 8
Findings from the sample


(Left tailed test at 5% level)
Since sample size is small though sigma is known we use Z test, since norm
Mean difference = -5
Std error = 
Test statistic t = mean diference / std error = 
df = n-1 =5
p value = 0.063
Answer: The answer is Yes.
Step-by-step explanation: Given in the question that Radric was asked to define "parallel lines" and he said that parallel lines are lines in a plane that do not have any points in common. We are to decide whether Radric's definition is valid or not.
Parallel lines are defined as lines in a plane which never meets or any two lines in a plane which do not intersect each other at any point are called parallel.
Thus, Radric's definition is valid.