Statistics Review

Statistics questions. Please open word document. Missing details attached (got to do with optimal sample size (n)).

Thanks.

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Select the correct answer (letter) to the question from the list of answers on the next page.

1. The ________ is the probability of observing a sample value as extreme as, or more extreme than the value observed, given that the null hypothesis is true.
2. The long-term behavior of a variable over an extended period of time is the ________
3. The variation within a year, such as retail sales during "back to school" period is called ______
4. A period of prosperity, followed by recession is called the ______________
5. When we plot a trend equation, the variable plotted along the horizontal axis is __________
6. Use the __________ to test if two sample variances come from the same or equal populations.
7. The coefficient of correlation can range between the two perfect correlations of ____________
8. If the coefficient of correlation is computed to be -0.80, this means as X increases Y ________
9. In a Chi-Square test of sales by days of the week at the 95% confidence level the critical value is _____.
10. With an r of -0.7 what proportion of the variation in Y is explained by variation in X? ______
11. With the regression equation of Y' = 3X + 25, when X equals 0, then Y' equals _______
12. If we raise the error allowed, E, in our survey results then we can use a _______ sample size, n.
13. The variable plotted on the vertical or Y - axis in a scatter diagram is the _______ variable.
14. If the null hypothesis contains an equal sign, =, then we need to do a _______ tailed test.
15.With a "level of significance" of 0.10, then the "level of confidence" is _________.
16. When the null hypothesis is rejected, we conclude the alternate hypothesis is __________
17. Given the same significance level, a ________ value of t will be required to reject the null hypothesis compared to the value of z required for rejection.
18.With a ________ tailed test the alternative hypothesis contains a < or > sign.
19. The null hypothesis is a claim about the value of the ___________________
20. The t distribution is continuous, has a mean of 0 and is more spread out than the ___________
21. Suggested levels of significance: political polling ______; consumer research ______; and quality control ______.
22. In a one-tailed test at alpha 0.05, with n = 21: z critical is ______; and t critical is_______.
23. To determine the equation for the regression line you (or Excel) use the ___________method.

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FILL-IN QUESTIONS

1. In Week 1 of RES/342 we determined the optimal sample size, n, using a three variable formula. Fill in the following table listing the three variables and specify the effect on n (either + or -) of increasing and decreasing each variable, one at a time.

VARIABLE EFFECT of INCREASE EFFECT of DECREASE

2. Given a Chi-Square problem where the sum of the observed frequencies (first column) is 500, the sum of the expected frequencies (second column) should equal _________and the sum of the observed frequencies minus the expected frequencies (third column) should equal _________.

3. Given a two-tailed hypothesis test where n = 40, the desired level of confidence is 95% and the population standard deviation is known, we would use the ______ test for the ______ level of significance and the critical value of __________.

4. Given an upper tail hypothesis test where n = 25, the desired level of confidence is 90% and the population standard deviation is unknown, we would use the ______ test for the ______ level of significance and the critical value of __________.

5. If the value of the test statistic falls in the "rejection region", our data are inconsistent with _______ and the decision should be to accept the _____________.

6. Degrees of freedom in a Chi-Square problem is dependent upon the number of _____________ while degrees of freedom in an F Distribution problem is dependent on _____________ in both the ___________________ and the _____________________.

7. Please fill in the second table given a 0.05 level of significance and the following data:
ROUTE MEAN TIME STANDARD DEVIATION OBSERVATIONS
Freeway 40 minutes 3 minutes 12 commuters
Surface Streets 45 minutes 5 minutes 8 commuters

Numerator Denominator Degrees of Freedom Numerator Degrees of Freedom Denominator F Critical Value Factor(s) & Levels Response Variable

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PROBLEMS (For full credit be sure to show your work.)

1.Your company wants to conduct a salary survey for the position of Accounting Assistant II. The estimated salary range is $4,500, the margin of error should be $100 and the desired level of confidence is 95%. What is the optimal sample size for this salary survey?

2. A restaurant that bills its house account monthly is concerned that the average monthly bill exceeds $200 per account. A random sample of twelve accounts is selected, resulting in the sample mean of $220 and a sample standard deviation of $12. The researchers have determined that they should test that the mean bill exceeds $200 at the 5% level of significance.

What is the Null Hypothesis? ___________
What is the Alternate Hypothesis? ____________
How many tail(s) in the test? __________
What test should the researchers use? _________________
Why do they use this test?
What is the critical value? ________________
If the calculated value for the test statistic is 5.77, then what have the researchers learned with the test?
Are the test results reliable?