A telephone counseling service for adolescents tested whether the length of calls would be affected by a special telephone system that had a better sound quality. Over the past several years, the lengths of telephone calls (in minutes) were normally distributed withμ=14andσ=8.The service arranged to have the special phone system loaned to them for one day. On that day, the mean length of the44calls they received was15minutes. Test whether the length of calls has changed using the 5% significance level. (b) Make a drawing of the distributions. The distribution of the general population is in blue and the distribution of means is in black. Choose the correct answer below.A.O B.OC.D.1415311424(c) Explain your answer to someone who knows about hypothesis testing with a sample of a single individual but who knows nothing about hypothesis testing withsamples of more than one individual,The distribution of means uses many samples ofV with each sample randomly taken from the population of individuals. Since the sample score couldV the hypothesis that the length of calls is affected by better call sound quality. In this situation,the researcher is finding a Z score of the sample's mean on a distribution of means instead of finding the Z score of a single individual on a distribution of singleoccur by chanceV the resultsindividuals. The sample mean is being treated as(d) Figure the 95% confidence interval.One can be 95% confident that the true population mean is betweenand(Type integers or decimals rounded to two decimal places as needed.)

Null Hypothesis: A hypothesis which is tested for plausible rejection is called the Null Hypothesis…

Answered: A telephone counseling service for…

MATLAB: An Introduction with Applications

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ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

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A telephone counseling service for adolescents tested whether the length of calls would be affected by a special telephone system that had a better sound quality. Over the past several years, the lengths of telephone calls (in minutes) were normally distributed with

μ=14

and

σ=8.

The service arranged to have the special phone system loaned to them for one day. On that day, the mean length of the

calls they received was

minutes. Test whether the length of calls has changed using the 5% significance level.

(b) Make a drawing of the distributions. The distribution of the general population is in blue and the distribution of means is in black. Choose the correct answer below.
A.
O B.
OC.
D.
14
15
31
14
24
(c) Explain your answer to someone who knows about hypothesis testing with a sample of a single individual but who knows nothing about hypothesis testing with
samples of more than one individual,
The distribution of means uses many samples of
V with each sample randomly taken from the population of individuals. Since the sample score could
V the hypothesis that the length of calls is affected by better call sound quality. In this situation,
the researcher is finding a Z score of the sample's mean on a distribution of means instead of finding the Z score of a single individual on a distribution of single
occur by chance
V the results
individuals. The sample mean is being treated as
(d) Figure the 95% confidence interval.
One can be 95% confident that the true population mean is between
and
(Type integers or decimals rounded to two decimal places as needed.)

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

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