
Concept explainers
(a)
Section 1:
To find: The error degrees of freedom for Model 1.
(a)
Section 1:

Answer to Problem 17E
Solution: There are 200 error degrees of freedom in Model 1.
Explanation of Solution
Calculation: The two models have been provided in the problem. Model 1 discusses the effect of Gene expression
Here, the variable
The degrees of freedom for the model are calculated as
The total degrees of freedom are calculated as:
The error degrees of freedom are calculated as
Section 2:
To find: The error degrees of freedom for Model 2.
Section 2:

Answer to Problem 17E
Solution: There are 199 error degrees of freedom in Model 2.
Explanation of Solution
Calculation: The two models have been provided in the problem. Model 2 discusses the effect of Gene expression
Here, the variable
The degrees of freedom for the model are calculated as
The total degrees of freedom are calculated as
The error degrees of freedom are calculated as
(b)
To test: The null hypothesis that “the serotonin gene regression coefficient is equal to zero” against “it is not equal to zero,” and the corresponding test statistic and its P-value in Model 1.
(b)

Answer to Problem 17E
Solution: The result is significant, that is, the regression coefficient for gene expression
Explanation of Solution
Calculation: The null hypothesis to test whether the variable gene expression
The alternative hypothesis that the variable for gene expression
The level of significance is 0.05. It is provided that
The test statistic
The critical value of test statistic
The P-value for the test is calculated as
Conclusion: The P-value is less than the level of significance. Also, the test statistic results are
Hence, the null hypothesis gets rejected, that is, the result is significant.
(c)
Section 1:
To test: The null hypothesis that “the serotonin gene regression coefficient is equal to zero” against “it is not equal to zero,” and the corresponding test statistic and its P-value for Model 2.
(c)
Section 1:

Answer to Problem 17E
Solution: The result is significant, that is, the regression coefficient for gene expression
Explanation of Solution
Calculation: The null hypothesis to test whether the regression coefficient for gene expression
The alternative hypothesis that the regression coefficient for gene expression
The level of significance is 0.05. It is provided that
The test statistic
The critical value of test statistic
The P-value for the test is calculated as
Conclusion: The P-value is less than the level of significance. Also, the test statistic results are
Hence, the null hypothesis gets rejected, that is, the result is significant.
Section 2:
To test: The null hypothesis that “the rule-breaking composite coefficient is equal to zero” against “it is not equal to zero,” and the corresponding test statistic and its P-value for Model 2.
Section 2:

Answer to Problem 17E
Solution: The result is significant, that is, the coefficient for rule-breaking composite
Explanation of Solution
Calculation: The null hypothesis to test whether the coefficient of rule-breaking composite
The alternative hypothesis that the explanatory variable rule-breaking composite
The level of significance is 0.05. It is provided that
The test statistic
The critical value of test statistic
The P-value for the test is calculated as
Conclusion: The P-value is less than the level of significance. Also, the test statistic results are
Hence, the null hypothesis gets rejected, that is, the result is significant.
(d)
Section 1
Whether there lies a positive relationship between “the serotonin gene receptor expression level” and “popularity” after adjusting for rule-breaking.
(d)
Section 1

Answer to Problem 17E
Solution: The coefficients of the variables “gene expression” and “rule breaking” are positive. It highlights that there lies a positive relationship between the coefficients of the two variables in both the models.
Explanation of Solution
Section 2
To find: The comparison of upsurge in popularity when the gene expression increases by one unit and the rule breaking composite remains fixed.
Section 2

Answer to Problem 17E
Solution: When the variable gene expression is increased by one unit, the popularity increases by 0.204 units in Model 1, and there is an increase in popularity by 0.161 units in Model 2.
Explanation of Solution
Calculation: The regression model for Model 1 can be written as
When the gene expression is increased by 1 unit, the increase in the popularity is calculated as follows:
Also, the regression model for Model 2 can be written as
When the gene expression is increased by 1 unit, keeping all other variables constant, the increase in popularity is calculated as follows:
Want to see more full solutions like this?
Chapter 11 Solutions
EBK INTRODUCTION TO THE PRACTICE OF STA
- Don’t solve questionarrow_forwardDon’t solve questionsarrow_forwardFred needs to choose a password for a certain website. Assume that he will choose an 8-character password, and that the legal characters are the lowercase letters a, b, c, ..., z, the uppercase letters A, B, C, ..., Z, and the numbers 0, 1, . . ., 9. (a) How many possibilities are there if he is required to have at least one lowercase letter in his password? (b) How many possibilities are there if he is required to have at least one lowercase letter and at least one uppercase letter in his password? (c) How many possibilities are there if he is required to have at least one lowercase letter, at least one uppercase letter, and at least one number in his password?arrow_forward
- a =1500, b=1700 what is percentage of a is barrow_forwardA 12-inch bar that is clamped at both ends is to be subjected to an increasing amount of stress until it snaps. Let Y = the distance from the left end at which the break occurs. Suppose Y has the following pdf. f(y) = { (a) Compute the cdf of Y. F(y) = 0 0 y -옴) 0 ≤ y ≤ 12 1- 12 y 12 Graph the cdf of Y. F(y) 1.0 0.8 0.6 0.4 0.2 y 2 6 8 10 12 F(y) F(y) F(y) 1.01 1.0ㅏ 1.0 0.8 0.6 0.4 0.2 0.8 0.8 0.6 0.4 ཨཱུ སྦེ 0.6 0.4 0.2 2 4 6 8 10 12 (b) Compute P(Y ≤ 5), P(Y > 6), and P(5 ≤ y ≤ 6). (Round your answers to three decimal places.) P(Y ≤ 5) = P(Y > 6) = P(5 ≤ y ≤ 6) = (c) Compute E(Y), E(y²), and V(Y). E(Y) = in E(Y2) v(x) = in 2 2 2 4 6 8 10 12 y 2 4 6 8 10 12arrow_forwardA restaurant serves three fixed-price dinners costing $12, $15, and $20. For a randomly selected couple dining at this restaurant, let X = the cost of the man's dinner and Y = the cost of the woman's dinner. The joint pmf of X and Y is given in the following table. p(x, y) 15 y 12 20 12 0.05 0.10 0.35 x 15 0.00 0.20 0.10 20 0.05 0.05 0.10 (a) Compute the marginal pmf of X. x 12 Px(x) Compute the marginal pmf of Y. y Pyly) 12 15 20 15 20 (b) What is the probability that the man's and the woman's dinner cost at most $15 each? (c) Are X and Y independent? Justify your answer. X and Y are independent because P(x, y) = Px(x) · Py(y). X and Y are not independent because P(x, y) =Px(x) · Pyly). X and Y are not independent because P(x, y) * Px(x) · Py(y). X and Y are independent because P(x, y) * Px(x) · Py(y). (d) What is the expected total cost, in dollars, of the dinner for the two people? $ (e) Suppose that when a couple opens fortune cookies at the conclusion of the meal, they find the…arrow_forward
- Let X = the time between two successive arrivals at the drive-up window of a local bank. If X has an exponential distribution with λ = 1, (which is identical to a standard gamma distribution with α = 1), compute the following. (If necessary, round your answer to three decimal places.) (a) the expected time between two successive arrivals (b) the standard deviation of the time between successive arrivals (c) P(X ≤ 1) (d) P(2 ≤ X ≤ 4) You may need to use the appropriate table in the Appendix of Tablesarrow_forwardIn each case, determine the value of the constant c that makes the probability statement correct. (Round your answers to two decimal places.) USE SALT (a) (c) 0.9842 (b) P(0 ≤ Z ≤ c) = 0.3051 (c) P(CZ) = 0.1335 You may need to use the appropriate table in the Appendix of Tables to answer this question.arrow_forwardSarrow_forward
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
- Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSONThe Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. FreemanIntroduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman





