1.1) (Ch. 7) Explain what a residual is (also known as residual of prediction).
e idea of “least squares” in regression (you need to fully read pp. 200-208 to understand).
3) What does it mean if b = 0?
4) What does it mean when r-squared is 0? What does it mean when r-squared is 1?
5) What is the difference in an unstandardized regression coefficient and the standardized regression coefficient?
6) If a report says test performance was predicted by number of cups of coffee (b = .94), what does the .94 mean? Interpret this. (For every one unit increase in ___,There is an increase in ___ )
7) If F (2,344) = 340.2, p < .001, then what is this saying in general about the regression model? (see p. 217)
8) Why should you be cautious in using unstandardized beta? (p. 218)
9) (Ch. 8) Explain partial correlation in your own words. In your explanation, explain how it is different from zero-order correlation (aka Pearson r).
10) (Ch. 9) What is the F statistic used to determine in multiple regression?
11) What is F when the null hypothesis is true?
12) In Table 9.4, which variable(s) are statistically significant predictors?
13) In Table 9.4, explain what it means if health motivation has b = .36 in terms of predicting number of exercise sessions per week.
14) What is the benefit of interpreting standardized beta weights? (see p. 264).
15) What happens if your predictor variables are too closely correlated?
16) Reflect on your learning. What has been the most difficult? How did you get through it? What concepts are still fuzzy to you? Is there anything you could share with me that would help me address how you learn best?
2.Fox News recently reported the results of a public opinion poll on supporting Trump that asked:
“Since he became the president,
Since he became the president, did President Trump act with the transparency and the integrity
that you expect from a president?” 675 voters responded the poll and 351 responded “YES.”
Assume that 40% of the U.S. population supports Trump.
a. Define a binary random variable, Y, for supporting Trump (Y=1) vs. not (Y=0).
Calculate the population mean (????????) and variance (????????
) for supporting Trump.
b. Calculate the sample mean ????̅ and the sample standard deviation of ????̅ (????????̅ ) for the poll.
c. Calculate the standard error of ????̅ and construct a 95% confidence interval from the
poll using ????̅ and its sample standard error.
d. Conduct a two-sided hypothesis test at 5% significance level to determine whether
40% of the U.S. population supports Trump. State the null and the alternative
hypotheses, calculate the test statistics and the associated p-value, and conclude. Is
the Fox News survey reliable? Why? Why Not?
e. Suppose that you wanted to design a survey that had a margin of error of at most 1%.
That is: the difference between the upper bound and the lower bound of the
confidence interval should be a maximum of 2 percentage points. For example, for
????̅ = 0.52 you are aiming for the 95 % CI to be [0.51 0.53].
How large should n be if the survey uses simple random sampling?
6.ATTACHED ARE GRAPHS
Q1 to Q4
The job satisfaction for the four occupational groups were used (lawyer, physical therapist, cabinetmakers, and
oups were used (lawyer, physical therapist, cabinetmakers, and system analysts). The results obtained for a sample of 5 individuals from each groups. Using the "ANOVA Output" below, please answer the following questions ( Use the significance level 5%).
Q1. The value of the test statistic is ____________
Q2. The p- value of the test is _________________
Q3. At the 5% significance level, the null hypothesis is rejected if the value of the F statistics is >= _________________
Q4. Interpret the ANOVA result at the 5% significance level. Is there any difference in the job satisfaction among the four occupational groups? Answer either yes or no. Explain the reason of your answer statistically.
Data from a Trucking Company is Southern California were utilized to examine the relationship among total daily travel time (y), miles to traveled (X1), and the number of deliveries (x2). Based on the "Regression Output" below, please answer the following questions.
Q5. The number of sample used in this regression analysis is______________
Q6. What is the value of the coefficient of determination?
Q7. What is the F test statistic value for the regression model significane test?
Q8. What is the predicted travel time for X1 =95, and X2= 6?
Q9. Is X2 (number of deliveries) related to Y (travel time)? Answer either yes or no. Explain the reason of your answer statistically.
ATTACHED ARE GRAPHS