According to a J.D. Power report, the average monthly cell phone bill for an individual was $70.60 in 2015. With new cell phone companies and new, no-contract plans from existing companies, it has been hypothesized that the mean cell phone bill could decrease. Assume the population of all monthly cell phone bills is left skewed with a standard deviation of $28.670. a) What conjecture has been made? The mean monthly cell phone bill has decreased from $70.60. The mean monthly cell phone bill has increased from $70.60. The mean monthly cell phone bill is $70.60. b) Completely describe the sampling distribution of the sample mean monthly bill when samples of size 81 are selected. Mean: μ¯ = Standard deviation: σ¯y = (round to 4 decimal places) Shape:the distribution of ¯y is Select an answer (not normally distributed)or (normally distributed ) because Select an answer (the population of cell phone bills is normally distributed), (the sample size is not large the population of cell phone bills is not normally distributed) ( the sample size is large) c) The sample of 81 individuals had an average monthly cell phone bill of $69.758. What is the probability of observing an average of $69.758 or less in the sample of individuals? z = (round to 2 decimal places) probability = (include 4 decimal places) Based on the probability found, what conclusion can be reached? If the sample size were increased to 127 individuals, between what two values would we expect 68% of the sample means to fall between

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Description: According to a J.D. Power report, the average monthly cell phone bill for an individual was $70.60 in 2015. With new cell phone companies and new, no-contract plans from existing companies, it has been hypothesized that the mean cell phone bill could

MATLAB: An Introduction with Applications

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According to a J.D. Power report, the average monthly cell phone bill for an individual was $70.60 in 2015. With new cell phone companies and new, no-contract plans from existing companies, it has been hypothesized that the mean cell phone bill could decrease. Assume the population of all monthly cell phone bills is left skewed with a standard deviation of $28.670.

a) What conjecture has been made?

The mean monthly cell phone bill has decreased from $70.60.
The mean monthly cell phone bill has increased from $70.60.
The mean monthly cell phone bill is $70.60.

Completely describe the sampling distribution of the sample mean monthly bill when samples of size 81 are selected.

Mean: μ¯ =
Standard deviation: σ¯y = (round to 4 decimal places)
Shape:the distribution of ¯y is Select an answer (not normally distributed)or (normally distributed ) because Select an answer (the population of cell phone bills is normally distributed), (the sample size is not large the population of cell phone bills is not normally distributed) ( the sample size is large)
c) The sample of 81 individuals had an average monthly cell phone bill of $69.758. What is the probability of observing an average of $69.758 or less in the sample of individuals?
z = (round to 2 decimal places)
probability = (include 4 decimal places)

Based on the probability found, what conclusion can be reached?
If the sample size were increased to 127 individuals, between what two values would we expect 68% of the sample means to fall between

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