Complete question:
He amount of time that a customer spends waiting at an airport check-in counter is a random variable with mean 8.3 minutes and standard deviation 1.4 minutes. Suppose that a random sample of n equals 47 customers is observed. Find the probability that the average time waiting in line for these customers is
a) less than 8 minutes
b) between 8 and 9 minutes
c) less than 7.5 minutes
Answer:
a) 0.0708
b) 0.9291
c) 0.0000
Step-by-step explanation:
Given:
n = 47
u = 8.3 mins
s.d = 1.4 mins
a) Less than 8 minutes:
P(X' < 8) = P(Z< - 1.47)
Using the normal distribution table:
NORMSDIST(-1.47)
= 0.0708
b) between 8 and 9 minutes:
P(8< X' <9) =![[\frac{8-8.3}{1.4/ \sqrt{47}}< \frac{X'-u}{s.d/ \sqrt{n}} < \frac{9-8.3}{1.4/ \sqrt{47}}]](https://tex.z-dn.net/?f=%20%5B%5Cfrac%7B8-8.3%7D%7B1.4%2F%20%5Csqrt%7B47%7D%7D%3C%20%5Cfrac%7BX%27-u%7D%7Bs.d%2F%20%5Csqrt%7Bn%7D%7D%20%3C%20%5Cfrac%7B9-8.3%7D%7B1.4%2F%20%5Csqrt%7B47%7D%7D%5D)
= P(-1.47 <Z< 6.366)
= P( Z< 6.366) - P(Z< -1.47)
Using normal distribution table,
0.9999 - 0.0708
= 0.9291
c) Less than 7.5 minutes:
P(X'<7.5) = ![P [Z< \frac{7.5-8.3}{1.4/ \sqrt{47}}]](https://tex.z-dn.net/?f=%20P%20%5BZ%3C%20%5Cfrac%7B7.5-8.3%7D%7B1.4%2F%20%5Csqrt%7B47%7D%7D%5D%20)
P(X' < 7.5) = P(Z< -3.92)
NORMSDIST (-3.92)
= 0.0000
Answer:
Part B: 8 and 2 (more answers ofc)
Part C: Two more dots on 6 (more than one answer tho)
Step-by-step explanation:
<em>Part B:</em>
The added number of dots is 39 at the beginning and the mean is 3.9. (39/10). Since we have to add 2 dots the equation will be (<em>39 + ? + ?) / 12 = Less than 3.9</em>. We also need the range to increase. This means that one of the blanks must be larger than 7 (the largest dot on the dot plot!) I just went with 8 to keep the mean as small as possible. This leaves 1 more blank to figure out. There are multiple answers to this problem but I went with 2 just because then the mean would be 3.5 a better answer than something like 3.58333333333.
<em>Part C:</em>
If you think about it all the dots added up should be 6x12 = 72. Currently all the dots add up to 60. 72-60 is 12. This means that 12 is equal to 2 dots. I guess you could also do 5 and 7, 8 and 4, etc.
G'day
-birb
Answer:
6 blue marbles
Step-by-step explanation:
20 marbles * .30 are blue = blue marbles
20 * .30 = 6 blue marbles
Considering the graph of the velocity of the car, it is found that the interval in which it was stopped at a traffic light was:
Between 3 and 4 minutes.
<h3>When is a car stopped at a traffic light?</h3>
When a car is stopped at a traffic light, the car is not moving, that is, it's velocity is of zero.
In this problem, the graph gives the <u>velocity as a function of time</u>, and it is at zero between 3 and 4 minutes, hence the interval in which it was stopped at a traffic light was:
Between 3 and 4 minutes.
More can be learned about the interpretation of the graph of a function at brainly.com/question/3939432
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