Answers claims that the mean length of all cell phone conversations in the United States is 3.25 minutes (3 minutes and 15 seconds). Assume that this is correct, and also assume that the standard deviation is 4.2 minutes. Suppose that, using a phone company’s records, we randomly sample 100 phone calls and make a histogram of the length of 100 phone calls. Is this histogram a display of the population distribution, the distribution of a sample, or the sampling distribution of means?

Step-by-step explanation:

a)

As the mean is less than the standard deviation, then this seems to be right skewed. [ANSWER]

b)

By central limit theorem, this distribution has the same mean as the original population.

u(X) = u = 3.25 [ANSWER]

c)

By central limit theorem, it will have a reduced standard deviation,

sigma(X) = sigma/sqrt(n) = 4.2/sqrt(100) = 0.42 [ANSWER]

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.