What’s the x value ?
1 answer:
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Answer:
a. If a sample of size 200 is taken, the probability that the proportion of successes in the sample will be between 0.47 and 0.51 is 41.26%.
b. If a sample of size 100 is taken, the probability that the proportion of successes in the sample will be between 0.47 and 0.51 is 30.5%.
Step-by-step explanation:
This problem should be solved with a binomial distribution sample, but as the size of the sample is large, it can be approximated to a normal distribution.
The parameters for the normal distribution will be
We can calculate the z values for x1=0.47 and x2=0.51:
We can now calculate the probabilities:
If a sample of size 200 is taken, the probability that the proportion of successes in the sample will be between 0.47 and 0.51 is 41.26%.
b) If the sample size change, the standard deviation of the normal distribution changes:
We can calculate the z values for x1=0.47 and x2=0.51:
We can now calculate the probabilities:
If a sample of size 100 is taken, the probability that the proportion of successes in the sample will be between 0.47 and 0.51 is 30.5%.
Answer:
The costs of the plan are $0.15 per minute and a monthly fee of $39
Step-by-step explanation:
Let
x ----> the number of minutes used
y ----> is the total cost
step 1
Find the slope of the linear equation
The formula to calculate the slope between two points is equal to
we have the ordered pairs
(100,54) and (660, 138)
substitute
step 2
Find the equation of the line in point slope form
we have
substitute
step 3
Convert to slope intercept form
Isolate the variable y
therefore
The costs of the plan are $0.15 per minute and a monthly fee of $39