Assume that blood pressure readings are normally distributed with a mean of 115
ID: 3295414 • Letter: A
Question
Assume that blood pressure readings are normally distributed with a mean of 115 and a standard deviation of 8. If 100 people are randomly selected, find the probability that their mean blood pressure will be less than 117. A) 0.8615 B) 0.9938 C) 0.8819 D) 0.0062 A coffee machine dispenses normally distributed amounts of coffee with a mean of 12 ounces and a standard deviation of standard deviation of 0.2 ounce. If a sample of 9 cups is selected, find the probability that the mean of the sample will be less than 12.1 ounces. Find the probability if the sample is just 1 cup. A) 0.4332: 06915 B) 0.9332: 0.1915 C) 0.9332: 0.6915 D) 0.4332: 0.1915 If the sample size is multiplied by 4, what happens to the standard deviation of the distribution of sample means? A) The standard error is doubled. B) The standard error is decreased by a factor of 4. C) The standard error is increased by a factor of 4. D) The standard error is halved. Find the probability that in 200 tosses of a fair six-sided die, a five will be obtained at least 40 times. A) 0.3875 B) 0.1210 C) 0.0871 D) 0.8810 Match the binomial probability P(xExplanation / Answer
Q.20 Pr (MEan blood pressure < 117 ; 115; 8/sqrt (100)) = Pr(MEan blood pressure < 117 ; 115; 0.8)
Z = ( 117 - 115)/ 0.8 = 2.5
so P-value = 0.9938 (OPtion B is correct)
Q.21 Mean = 12 ounces
standard deviation = 0.2 ounce
sample size = 9
standard error of the mean = 0.2/ sqrt (9) = 0.2/3 = 0.067
Pr (sample mean < 12.1; 12; 0.067)
Z = ( 12.1 - 12)/ 0.067 = 1.5
P - value = 0.9332
if sample size is 1 then Z = (12.1 - 12)/ 0.2 = 0.5
P - value = 0.6915
Q.22 If sample size is multiplied by 4, standard deviation of deviation of the means will be inversly square root of sample size . That means it will be 1/2 times. Option D is correct.
Q.23 P (5) = 1/6
So expected value = 200 * 1/6 = 33.33
standard deviation of the expected value = sqrt (1/6 * 5/6 * 200) = 5.27
Z = ( 40 - 33.33)/ 5.27 = 1.265
Pr ( P5 > 40 ; 33.33; 5.27) = 1 - ( 1.265)
where is the normal cumulative distribution function. and apply correction facor
Pr ( P5 > 39.5 ; 33.33; 5.27) = 1 - ( 1.17) = 1 - 0.879 = 0.1210
Q>24 = Option B is correct. there are fewer than 40 successes.
Q.25 There are more than 12 leeft handedstudents in the class. P(X >12) Option B is correct.