What are all the factors of 43?
2 answers:
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Answer:
The upper limit of a 95% confidence interval for the population mean would equal 83.805.
Step-by-step explanation:
The standard deviation is the square root of the variance. Since the variance is 25, the sample's standard deviation is 5.
We have the sample standard deviation, not the population, so we use the t-distribution to solve this question.
T interval:
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 15 - 1 = 14
Now, we have to find a value of T, which is found looking at the t table, with 14 degrees of freedom(y-axis) and a confidence level of 0.95(). So we have T = 1.761
The margin of error is:
M = T*s = 1.761*5 = 8.805.
The upper end of the interval is the sample mean added to M. So it is 75 + 8.805 = 83.805.
The upper limit of a 95% confidence interval for the population mean would equal 83.805.
Answer:
(a) The probability that a text message user receives or sends three messages per hour is 0.2180.
(b) The probability that a text message user receives or sends more than three messages per hour is 0.2667.
Step-by-step explanation:
Let <em>X</em> = number of text messages receive or send in an hour.
The random variable <em>X</em> follows a Poisson distribution with parameter <em>λ</em>.
It is provided that users receive or send 62.7 text messages in 24 hours.
Then the average number of text messages received or sent in an hour is: .
The probability of a random variable can be computed using the formula:
(a)
Compute the probability that a text message user receives or sends three messages per hour as follows:
Thus, the probability that a text message user receives or sends three messages per hour is 0.2180.
(b)
Compute the probability that a text message user receives or sends more than three messages per hour as follows:
P (X > 3) = 1 - P (X ≤ 3)
= 1 - P (X = 0) - P (X = 1) - P (X = 2) - P (X = 3)
Thus, the probability that a text message user receives or sends more than three messages per hour is 0.2667.