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Suppose that you are attempting to estimate the annual income of 1100 families. In order to use the infinite standard deviation formula, what sample size, n, should you use? (n / N ) ≤0. N = 1100 n ≤ (0.05 x 1100 ) = 55 n ≤ 55 The sample size (n) has to be less than or equal to 55
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Suppose that you are attempting to estimate the annual income of 1100 families. In order to use the infinite standard deviation formula, what sample size, n, should you use?
MATH 110 Module 5 Exam
Suppose that you take a sample of size 18 from a population that is not normally distributed. Can the sampling distribution of xx be approximated by a normal probability distribution? No. The population is not normally distributed, therefore, we need a sample size of at least 30 to approximate by a normal probability distribution.
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Suppose that you take a sample of size 18 from a population that is not normally distributed. Can the sampling distribution of xx be approximated by a normal probability distribution? No, the sampling distribution of xbar cannot be approximated by a normal probability distribution because the population is "not normally" distributed and the sample size is less than 30.
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Exam Page 3 Suppose that in a large hospital system, that the average (mean) time that it takes for a nurse to take the temperature and blood pressure of a patient is 170 seconds with a standard deviation of 40 seconds. What is the probability that 20 nurses selected at random will have a mean time of 165 seconds or less to take the temperature and blood pressure of a patient? u = 170 o = 40 n = 20 xbar = 165 xbar - u = 165 - 170 = - 5 oxbar = o / √n 40 / √20 = 8. z = ((xbar - u) / oxbar) ( - 5 / 8.94) = - 0.559 = - 0.56 look on chart ---> 0. P(Z < - 0.56) = 0. 0.2877 probability that if 20 nurses were selected at random, that they would have a mean time of 165 seconds or less in time spent taking a patients temp. and b/p.
Answer Key
Suppose that in a large hospital system, that the average (mean) time that it takes for a nurse to take the temperature and blood pressure of a patient is 170 seconds with a standard deviation of 40 In order to use infinite standard deviation formula, we should have: n≤0.05(1100) n≤ So, the sample size should be less than 55.
Suppose that in a very large city 9.8 % of the people have more than two jobs. Suppose that you take a random sample of 70 people in that city, what is the probability that 9 % or more of the 70 have more than two jobs? Now we find the z-score: We want P(Z>-0.23). From the standard normal table, we find: P(Z>-.23)=1- P(Z<-.23)=1-.40905=.59095. So there is a .60257 probability that the percentage of the sample that have more than two jobs is more than 9 %.
P(Z < 0.12) = 0.
Out of a random sample of 70 people there is a 0.591 probability that 9% or more of them have more than 2 jobs.
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