1. 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
...
1. 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)?
There are 3 possibilities of rolling a 4 three times in a row. Because there is a total probability
of 36 (2 dice, 6 possible answers)
and could get 3 possible combinations of getting a 4, we can calculate 36-(3/36)= 35.92.
Therefore, the probability of rolling a 4 three times in a row is 3/36 x 3/36 x 3/36 = 0.00694.
1st die
2nd
die
1 3
3 1
2 2
2. Population A and Population B both have a mean height of 70.0 inches with an SD of 6.0. A
random sample of 30 people is picked from population A, and random sample of 50 people is
selected from Population B. Which sample mean will probably yield a more accurate estimate of its
population mean? Why?
SEM(A): 6/SQRT(30) = 1.095
SEM(B): 6/SQRT(50) = 0.848
Sample B will yield the more accurate population mean because the SEM decreases as the
population increases, meaning that we achieve a closer mean of the overall mean.
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 7.8mm with an SD of 2.1. Using a t distribution
table, what are the confidence limits for a 95% confidence interval? For a 99% confidence interval?
SEM 2.1/SQRT(50) = 0.2969
SEM = .2969
95% 99%
T-dist. 2.01 2.66
CI 7.8mm +/- (2.01 X 0.2969) 7.8mm +/- (2.66 X 0.2969)
UCL= 8.40mm, LCL=
7.20mm UCL = 8.59mm, LCL =7.03mm
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
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