Q1: A random sample of 36 students shows an average age of 24 years old with a know population standard deviation of 6 years , The standard error of the ssample means is ? (how to calcaulate)
Q2: The probability of obtaining a sample mean large than 26 is ? (how to calcaulate ?)
STATISTICS
2008-05-16 7:00 pm
回答 (2)
2008-05-16 9:56 pm
✔ 最佳答案
Q.1 Since the sample size greater than 30, the random variable (age) follows Normal Distribution.
Standard Error of the Sample Mean
= Z(elva/2) * Standard Deviation / Square Root of n
= Z(elva/2) * 6/ square root of 36
= Z(elva/2)
Q.2
P(X greater than 26)
= P(Z greater than (26-24)/(6/square root of 36) )
= P(Z greater than 2)
= 0.022750132
2008-05-17 20:51:41 補充：
The probability of uncertainty (elva).
Find your answer from normal table with respect to different elva.
e.g. elva = 0.05, Z(elva/2) = 1.96
elva = 0.1, Z(elva/2) = 1.645
2008-05-19 9:19 pm
唔該哂...謝謝
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