The average local cell phone call length was reported to be 2.27 minutes. A random sample of 20 phone calls showed an average of 2.98 minutes in length with a standard deviation of 0.98 minutes.
At α = 0.05 can it be concluded that the average differs from the population average?
Report your answer to two decimal places.
Note: Find the test statistic ONLY to test this claim using an appropriate formula. You must show your work.

Yes, at α = 0.05 it can be concluded that the average differs from the population average.

Step-by-step explanation:

We are given that the average local cell phone call length was reported to be 2.27 minutes. A random sample of 20 phone calls showed an average of 2.98 minutes in length with a standard deviation of 0.98 minutes.

Let = population average local cell phone call length

SO, Null Hypothesis, : = 2.27 minutes  {means that the average is same as that of population average}

Alternate Hypothesis, : 2.27 minutes  {means that the average differs from the population average}

The test statistics that will be used here is One-sample t test statistics because we don't know about population standard deviation;

                T.S.  =    ~

where,  = sample average call length = 2.98 minutes

            s = sample standard deviation = 0.98 minutes

            n = sample of phone calls = 20

So, test statistics  =    ~

                               =  3.24

Now, at 0.05 level of significance the t table gives critical values between -2.093 and 2.093 at 19 degree of freedom for two-tailed test. Since our test statistics does not lie within these range of critical values so we have sufficient evidence to reject our null hypothesis as test statistics will fall in the rejection region.

Therefore, we conclude that the average differs from the population average.

answer: a video game has three difficulty levels: easy, medium, and expert. the game's scoring works in such a way that a player has to score a fixed number of points to advance to the next level, and then the scoring starts over. the total score needed to clear all three difficulty levels is 7,500. two times the number of points needed to clear the easy level is 500 more than the number of points needed to clear the medium level. twice the number of points needed to clear the medium difficulty level is 1,500 more than the number of points needed to clear the expert level. if x, y, and z represent the easy, medium, and expert levels, respectively, and a is the coefficient matrix of the system of equations modeling this situation, identify the inverse matrix, a-1, and the solution matrix, x, of the system of equations.

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rauschg

rauschg · hand

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it is a secret for it not to be compromised sorry

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