SOLUTION: I need to answer for class right now can someone help me please! Consider a population with u=71.7 and o=3.95 . (A) Calculate the z-score for x = 70.3 from a sample of size 41.

Algebra ->  Probability-and-statistics -> SOLUTION: I need to answer for class right now can someone help me please! Consider a population with u=71.7 and o=3.95 . (A) Calculate the z-score for x = 70.3 from a sample of size 41.      Log On


   

Question 407358: I need to answer for class right now can someone help me please!
Consider a population with u=71.7 and o=3.95 .
(A) Calculate the z-score for x = 70.3 from a sample of size 41.
(B) Could this z-score be used in calculating probabilities? Why or why not?
Found 2 solutions by jim_thompson5910, sunsetatdawn:
Answer by jim_thompson5910(35256) About Me  (Show Source):
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A)

Recall that the z score is z=%28x-mu%29%2Fsigma, so the z score of x=70.3 is z=%2870.3-71.7%29%2F%283.95%29=-0.354

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B)

Yes it can be used to calculate probabilities. Your book will most likely have standard normal tables in the back, which will help you calculate probabilities.


For example, a common value in the table is P(Z < 0) = 0.5


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Answer by sunsetatdawn(4) About Me  (Show Source):
You can put this solution on YOUR website!
This answer left one thing out of the formula for answer A. Though, it is probably too late to be helpful to you now, it may be to someone else. The formula for A would be (70.3 - 71.7)/(3.95/41) and solve from there. When using a sample, the formula is the same as was given to find a z score for a whole population, except you have to divide the standard deviation in the denominator by n(the number in the sample).