
(a)
Delineate whether it is usual that an investigator would get as many pairs as Person R with the treatment animal having the heavier cortex.
(a)

Answer to Problem 12RE
There is no evidence that there appears to be 50-50 chance for each animal in a pair to have heavier cortex.
Explanation of Solution
Let ‘T’ represent the treatment and ‘C’ represent the control.
The cortex weight of the animal in the treatment is 689 milligrams and the cortex weight of the animal in the control is 657 milligrams.
Based on the given information, the following values are known.
On observing the table, 52 pairs have higher value for the treatment and 7 have higher value for the control group.
Let ‘0’ represent the tails.
Let ‘1’ represent the heads.
In this scenario, consider a box containing 2 tickets in which 1 ticket is labeled 1 and 1 ticket is labeled 0.
Therefore, the null hypothesis states that the number of higher values for the treatment is the sum of 59 random draws (with replacement) from a box containing a ticket labeled 1 and a ticket labeled 0.
On the other hand, the alternative hypothesis states that there are many higher values.
The
The expected value is obtained using the product of the percentage of 1’s in the box and the number of draws.
Standard deviation of the box:
Standard error of the sum:
The known values are given below:
The formula for z-score is as follows:
The z-score is obtained as given below:
The probability P is given below:
Using the standard normal table, the value corresponding to
Remaining calculation:
Since the P-value is less than any of the level of significance, it is unusual to obtain a difference in the sample percentage of 50% when there is difference in the population percentage and thus, the difference does not appear due to chance variation.
Therefore, there is evidence that there appears to be no 50-50 chance for each animal in a pair to have a heavier cortex.
(b)
Obtain the average and SD of the difference.
State whether there is evidence that the treatment has no effect.
(b)

Answer to Problem 12RE
There is no evidence that the treatment has no effect.
Explanation of Solution
Based on the given information, the following values are known:
The mean of the sample is as given below:
The standard deviation is as given below:
The standard error of the sum is given below:
The standard error of the average is the standard error of the sum divided by the number of draws, which is given below:
The test hypotheses are given below:
Let
Null hypothesis:
Alternative hypothesis:
The formula for test statistic is as follows:
Known values:
The z-score is obtained as given below:
The P-value is given below:
Using the standard normal table, the value corresponding to
Since the P-value is less than any of the level of significance, it is unusual to obtain a difference in the sample average of 36.2373 when there is difference in the population averages and thus, the difference does not appear due to chance variation.
Therefore, the treatment appears to have an effect.
(c)
Discuss about the point of precaution and also state whether it is a good idea.
(c)

Answer to Problem 12RE
The point of precaution is a good idea.
Explanation of Solution
In this context, a precaution was made that the dissection of a set of littermates were executed at random and the person performing the partition will not know which cage the rate came from.
The random order of the execution of the dissections is important because it is possible that the second cortex weight will always be more accurate than the first cortex weight due to the experience that is influencing the weighing.
It is also important that the person performing the dissections does not know which littermates received which treatments. Hence, a person could influence the results when he/she knows which treatments were received by those littermates.
Therefore, the precautions were made to make the weighing more accurate and less influenced by bias.
Thus, the point of precaution is a good idea.
Want to see more full solutions like this?
Chapter 26 Solutions
Statistics
- The accompanying data represent the weights (in grams) of a simple random sample of 10 M&M plain candies. Determine the shape of the distribution of weights of M&Ms by drawing a frequency histogram. Find the mean and median. Which measure of central tendency better describes the weight of a plain M&M? Click the icon to view the candy weight data. Draw a frequency histogram. Choose the correct graph below. ○ A. ○ C. Frequency Weight of Plain M and Ms 0.78 0.84 Frequency OONAG 0.78 B. 0.9 0.96 Weight (grams) Weight of Plain M and Ms 0.84 0.9 0.96 Weight (grams) ○ D. Candy Weights 0.85 0.79 0.85 0.89 0.94 0.86 0.91 0.86 0.87 0.87 - Frequency ☑ Frequency 67200 0.78 → Weight of Plain M and Ms 0.9 0.96 0.84 Weight (grams) Weight of Plain M and Ms 0.78 0.84 Weight (grams) 0.9 0.96 →arrow_forwardThe acidity or alkalinity of a solution is measured using pH. A pH less than 7 is acidic; a pH greater than 7 is alkaline. The accompanying data represent the pH in samples of bottled water and tap water. Complete parts (a) and (b). Click the icon to view the data table. (a) Determine the mean, median, and mode pH for each type of water. Comment on the differences between the two water types. Select the correct choice below and fill in any answer boxes in your choice. A. For tap water, the mean pH is (Round to three decimal places as needed.) B. The mean does not exist. Data table Тар 7.64 7.45 7.45 7.10 7.46 7.50 7.68 7.69 7.56 7.46 7.52 7.46 5.15 5.09 5.31 5.20 4.78 5.23 Bottled 5.52 5.31 5.13 5.31 5.21 5.24 - ☑arrow_forwardく Chapter 5-Section 1 Homework X MindTap - Cengage Learning x + C webassign.net/web/Student/Assignment-Responses/submit?pos=3&dep=36701632&tags=autosave #question3874894_3 M Gmail 品 YouTube Maps 5. [-/20 Points] DETAILS MY NOTES BBUNDERSTAT12 5.1.020. ☆ B Verify it's you Finish update: All Bookmarks PRACTICE ANOTHER A computer repair shop has two work centers. The first center examines the computer to see what is wrong, and the second center repairs the computer. Let x₁ and x2 be random variables representing the lengths of time in minutes to examine a computer (✗₁) and to repair a computer (x2). Assume x and x, are independent random variables. Long-term history has shown the following times. 01 Examine computer, x₁₁ = 29.6 minutes; σ₁ = 8.1 minutes Repair computer, X2: μ₂ = 92.5 minutes; σ2 = 14.5 minutes (a) Let W = x₁ + x2 be a random variable representing the total time to examine and repair the computer. Compute the mean, variance, and standard deviation of W. (Round your answers…arrow_forward
- The acidity or alkalinity of a solution is measured using pH. A pH less than 7 is acidic; a pH greater than 7 is alkaline. The accompanying data represent the pH in samples of bottled water and tap water. Complete parts (a) and (b). Click the icon to view the data table. (a) Determine the mean, median, and mode pH for each type of water. Comment on the differences between the two water types. Select the correct choice below and fill in any answer boxes in your choice. A. For tap water, the mean pH is (Round to three decimal places as needed.) B. The mean does not exist. Data table Тар Bottled 7.64 7.45 7.46 7.50 7.68 7.45 7.10 7.56 7.46 7.52 5.15 5.09 5.31 5.20 4.78 5.52 5.31 5.13 5.31 5.21 7.69 7.46 5.23 5.24 Print Done - ☑arrow_forwardThe median for the given set of six ordered data values is 29.5. 9 12 23 41 49 What is the missing value? The missing value is ☐.arrow_forwardFind the population mean or sample mean as indicated. Sample: 22, 18, 9, 6, 15 □ Select the correct choice below and fill in the answer box to complete your choice. O A. x= B. μεarrow_forward
- Why the correct answer is letter A? Students in an online course are each randomly assigned to receive either standard practice exercises or adaptivepractice exercises. For the adaptive practice exercises, the next question asked is determined by whether the studentgot the previous question correct. The teacher of the course wants to determine whether there is a differencebetween the two practice exercise types by comparing the proportion of students who pass the course from eachgroup. The teacher plans to test the null hypothesis that versus the alternative hypothesis , whererepresents the proportion of students who would pass the course using standard practice exercises andrepresents the proportion of students who would pass the course using adaptive practice exercises.The teacher knows that the percent confidence interval for the difference in proportion of students passing thecourse for the two practice exercise types (standard minus adaptive) is and the percent…arrow_forwardCarpetland salespersons average $8,000 per week in sales. Steve Contois, the firm's vice president, proposes a compensation plan with new selling incentives. Steve hopes that the results of a trial selling period will enable him to conclude that the compensation plan increases the average sales per salesperson. a. Develop the appropriate null and alternative hypotheses.H 0: H a:arrow_forwardتوليد تمرين شامل حول الانحدار الخطي المتعدد بطريقة المربعات الصغرىarrow_forward
- The U.S. Postal Service will ship a Priority Mail® Large Flat Rate Box (12" 3 12" 3 5½") any where in the United States for a fixed price, regardless of weight. The weights (ounces) of 20 ran domly chosen boxes are shown below. (a) Make a stem-and-leaf diagram. (b) Make a histogram. (c) Describe the shape of the distribution. Weights 72 86 28 67 64 65 45 86 31 32 39 92 90 91 84 62 80 74 63 86arrow_forward(a) What is a bimodal histogram? (b) Explain the difference between left-skewed, symmetric, and right-skewed histograms. (c) What is an outlierarrow_forward(a) Test the hypothesis. Consider the hypothesis test Ho = : against H₁o < 02. Suppose that the sample sizes aren₁ = 7 and n₂ = 13 and that $² = 22.4 and $22 = 28.2. Use α = 0.05. Ho is not ✓ rejected. 9-9 IV (b) Find a 95% confidence interval on of 102. Round your answer to two decimal places (e.g. 98.76).arrow_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





