# BA 578 Assignment Summer II 2014

November 28, 2016

Question

Part D: Must show all your work step by step in order to receive the full credit; Excel is not allowed. (61-71)

Use the following information from a normal population with mean ? = 52 and variance ?2 = 22.5 to calculate the following questions.

find P (X >55 )

find P (50?X?60)

find P (X?55)

A random sample from a population with mean and standard deviation produced the following sample information:

n =110 x = 699 s = 20.4

Find a 95% confidence interval for the mean ?. Interpret this interval.

Find a 99% confidence interval for the mean ?. Interpret this interval.

Consider the following hypothesis test.

Ho: µ = 17

Ha: µ ? 17

A sample of 25 gives a sample mean of 14.2 and sample variance of 25.

At ? = 0.05, what is the rejection rule?

Compute the value of the test statistic

What is the p-value?

Consider the following hypothesis test.

Ho: ? = 15

Ha: ? ? 15

A sample of 50 gives a sample mean of 14.2 and sample standard deviation of 5.

At ? = 0.02, what is the rejection rule?

Compute the value of the test statistic z.

What is the p-value?

Consider the following hypothesis test

Ho: µ ? 10

Ha: µ < 10

A sample of 50 provides a sample mean of 9.46 and sample variance of 4.

At ? = 0.05, what is the rejection rule?

Reject null if z 0, what statistical decision should be made at 5% level.

What is the standard error of estimate? Can you use this statistic to assess the model’s fit? If so, how?

What is the coefficient of determination, and what does it tell you about the regression model?

What is the coefficient of determination, adjusted for degrees of freedom? Explain how this statistic and the statistic referred to in part (f) help you to determine how well the model fits the data.

Test the overall utility of the model. What does the p-value of the test statistic tell you?

For the following ANOVA table are the results from treating 4 cultures with 6 observations for each culture. The enzymes are contained in test tubes with differing levels of enzymes applied.

Source of Variation df SS MS F

Treatment 180

Error 60

Total

What are the null and alternate hypotheses?

What is your decision rule, Use ?=0.05

Is there a difference among the means?

A metropolitan bus system sampler’s rider counts on one of its express commuter routes for a week. Use the following data to establish whether the rider ship is evenly balanced by day of the week. Let ?=0.05

Day Monday Tuesday Wednesday Thursday Friday

Rider Count 10 34 21 57 44

Is the ?2 value significant at 5% level of significance

Write the conclusion for this question.

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