BST 322 Week 2 Assignment
 What is the probability of rolling a four in the gambling dice game of craps (given two six sided dice)? What is the probability that a player can roll a four 3 times in a row (assume that rolling the dice each time does not affect the outcome of the next roll)?
TIPS: Probability is a fraction or decimal = Number of ways it can happen/Total Number of Possibilities
STEP A: Total Number of possibilities = 36 as follows:
(1,1) 
(1,2) 
(1,3) 
(1,4) 
(1,5) 
(1,6) 
(2,1) 
(2,2) 
(2,3) 
(2,4) 
(2,5) 
(2,6) 
(3,1) 
(3,2) 
(3,3) 
(3,4) 
(3,5) 
(3,6) 
(4,1) 
(4,2) 
(4,3) 
(4,4) 
(4,5) 
(4,6) 
(5,1) 
(5,2) 
(5,3) 
(5,4) 
(5,5) 
(5,6) 
(6,1) 
(6,2) 
(6,3) 
(6,4) 
(6,5) 
(6,6) 
STEP B: Determine the number of ways it can happen for a 4 using two dice.
STEP C: Form the Fraction: Number of ways it can happen/Total Possibilities.
For the 2^{nd} part of Q1 use the multiplicative/consecutive rule
 Population A and Population B both have a mean height of 70.0 inches with an SD of 6.0. A random sample of 35 people is picked from population A, and random sample of 65 people is selected from Population B. Which sample mean will probably yield a more accurate estimate of its population mean? Why?
TIP: See page 90. You can also calculate the SEM and compare the two values.
3. Suppose we obtained data on vein size after application of a nitroglycerin ointment in a sample of 50 patients. The mean vein size is found to be 9.7mm with an SD of 2.5. Using a t distribution table, what are the confidence limits for a 95% confidence interval? For a 99% confidence interval?
TIP: Please use either StatCrunch – 1SAMPLE TTEST (Summary) on a blank sheet or the formula on page 94.
4. In a pilot study evaluating the use of a new drug to lower resting heart rates (HR) of patients, the following data was recorded:
Subject # 
Resting HR 

001 
72 

002 
88 

003 
71 

004 
87 

005 
65 

006 
77 

007 
79 

008 
59 

009 
75 

010 
68 

011 
78 

012 
90 

013 
91 

014 
81 

015 
85 

016 
75 

017 
69 

Given that the average resting HR of the general population for this study is 72, use StatCrunch to perform the appropriate t test. What is the value of t? Using an alpha of 0.05, is the t statistic significant? Why? What are the confidence limits for a 95% confidence interval here and what do they mean for this patient group? Copy and Paste your work from StatCrunch into your Word document submission.
TIP: USE STATCRUNCH – 1SAMPLE. Remember to input 72 as per the screen below
5. Write one or two sentences that could be used to report the results obtained for the ttest in Exercise 4.
TIP: For the report, please use the specific ttest value, the pvalue from the test, state whether the result is significant or not and whether you would reject/accept the null hypothesis
6. For which of the following situations is the independent groups ttest appropriate (if inappropriate, why?):
a. The independent variable is infant birth weight at one week (normal vs high); the dependent variable is resting heart rate.
b. The independent variable is radiation treatment on throat cancer patients (after a low dose and then a high dose treatment); the dependent variable is white blood cell count.
c. The IV is infant birth weight (low vs normal vs high); the DV is number of days absent from school in first grade.
d. The IV is gender (male vs female); the DV is compliance vs noncompliance with a medication regimen.
e. The independent variable is married status (single vs married); the dependent variable is happiness measured on a scale from 1 to 50
TIP:
Determine the characteristics of independent groups for ttests? How many groups are there in the situation? Are there 2 groups in the situation? Are they independent groups and is the DV interval/ratio? If the answer is “yes” to the 3 questions, the situation is APPROPRIATE and you should state that it is so. If one or more of the conditions is/are not present, then the test is inappropriate.
7. For which of the following situations is the dependent groups ttest appropriate (if not appropriate, why?)
a. The IV is presence or absence of conversation directed to comatose patients (same patients with and without conversation); the DV is the patients’ intracranial pressure.
b. The IV is birth type (home vs hospital); the DV is perceived functional ability of the patient 48 hours after surgery.
c. The IV is time since incarceration (1 months vs 3 months vs 6 months); the DV is body weight.
d. The IV is menopausal state (pre vs post) in the same women over time; the DV is attitudes toward menopause.
e. The IV is nap therapy for narcoleptics (same patients before vs after treatment); the DV is the type of nap they had the following week (had unplanned vs didn’t have unplanned nap).
TIP: Determine the characteristics of dependent groups for ttests. How many groups are there in the situation? Are there 2 groups in the situation? Are they dependent groups and is the DV interval/ratio? If the answer is “yes” to the 3 questions, the situation is APPROPRIATE and you should state that it is so. If one or more of the conditions is/are not present, then the test is inappropriate
8. Suppose we wanted to test the hypothesis that a control group of cancer patients (Group 1) would report higher mean pain ratings than an experimental group receiving special massage treatments (Group 2). Use the following information. Compute a tstatistic for independent groups:
mean group 1 = 79.1 SD^{2}_{1} = 42.1 n_{1} = 25
mean group 2 = 74.1 SD^{2}_{2} = 39.7 n_{2 }= 25
What are the degrees of freedom and the value of t ? Using α=0.05 for a twotailed test, is this t statistic significant? Show your calculations (or StatCrunch output) for full credit.
9. Write one or two sentences that could be used to report the results obtained for the ttest in Exercise 8.
TIP: For the report, please use the ttest value, the pvalue from the test, state whether the result is significant or not and whether you would reject/accept the null hypothesis.
10. For each of the following t values, indicate whether the t is statistically significant for a twotailed test, at the specified alphas:
a. t = 2.90, df = 25, α = 0.001
b. t = 2.00, df = 25, α = 0.05
c. t = 5.52, df = 10, α = 0.01
d. t = 2.02, df = 20, α = 0.05
TIP: Use the tables on page 412 to obtain your answer. If the tvalue is GREATER than the value in the critical/tabled value, the result is statistically significant.
11. For each of the following situations, indicate whether ANOVA is appropriate; if not appropriate, the reason why not; and, if appropriate, the type of ANOVA that would be used (i.e., oneway, repeated measures, etc.)
a. The IVs are ethnicity (Asian, White, African American, Hispanic) and gender (male vs female); the DV is serum cholesterol levels.
b. The IV is smoking status – smokers vs nonsmokers; the DV is healthrelated hardiness as measured on a 20item scale.
c. The IV is maternal breast feeding status (breastfeeds daily vs breastfeeds at least 13 times/week vs doesn’t breastfeed); the DV is maternal bonding with infant, as measured on a 20item selfreport scale.
d. The IV is treatment group for patients with druginduced shivering (extremity wraps vs high room temp vs normal room temp without wraps) different patients used for each treatment; the DV is myocardial oxygen consumption (measured in ml O_{2}/min per 100g of tissue).
e. The IV is length of gestation (preterm vs term vs postterm) using the same multiple birth mothers over time; the DV is blood pressure 10 minutes post delivery.
TIP: Determine the characteristics of ANOVAs. How many groups are there in the situation? Are there 3 groups in the situation? Is the DV interval/ratio? If the answer is “yes” to all the questions, the situation is APPROPRIATE and you should state that it is so. If one or more of the conditions is/are not present, then the test is inappropriate. If it is APPROPRIATE, please state which type of ANOVA it is.
12. Suppose we wanted to compare the somatic complaints (as measured on a scale known as the Physical Symptom Scale or PSS) of three groups of people: nonsmokers, smokers, and people who recently quit smoking. Using the following data for PSS, do a oneway ANOVA to test the hypothesis that the population means are equal:
Nonsmokers Smokers Quitters
19 31 30
28 29 22
29 22 30
20 20 29
25 28 34
Using StatCrunch, determine the means for the three groups and compute the sums of squares, degrees of freedom, and mean squares for these data. What is the value of F? Using an alpha of 0.05, is the F statistic significant? Why? Copy and Paste your work from StatCrunch into your Word document submission.
TIP: Conduct a oneway ANOVA using STATCRUNCH
13. A new motorcycle is being developed to meet new gas mileage standards recently passed by the federal government. An engineer tested three model designs by randomly assigning the motorcycles in a blind study (the riders recorded the mileage but did not know the design of the motorcycle, only its code). The data in miles per gallon (MPG) for the three designs is listed below:
X1 
B1 
Z1 
45 
55 
54 
62 
55 
52 
50 
54 
41 
65 
44 
40 
62 
52 
38 
50 
69 
39 
50 
58 
51 
58 
45 
64 
Using StatCrunch, determine the means for the three groups and compute the sums of squares, degrees of freedom, and mean squares for these data. What are the hypotheses to be tested here? What is the value of F? Using an alpha of 0.05, is the F statistic significant? Why? Copy and Paste your work from StatCrunch into your Word document submission for full credit.
TIP: Another example using 1way ANOVA in StatCrunch
14. For each of the following F values, indicate whether the F is statistically significant at the specified alpha level:
a. F = 4.80, df = 4, 40 α = 0.01
b. F = 5.00, df = 3, 60, α = 0.001
c. F = 3.45, df = 3, 27, α = 0.05
d. F = 1.99, df = 2, 150, α = 0.01
e. F = 3.09, df = 2, 250, α = 0.05
TIP: Use the textbook ANOVA tables on pages 413 to 415 [look to see if the alpha value for each of your Fstatistic is correct for the table you have selected].
If the Fstatistic is GREATER than the value in the critical/tabled value, the result is statistically significant.